TL;DR version:
begin with 6/10;
add 2 if you have no problems with levelscaling and/or a mod comes out that removes levelscaling;
add 1 if a mod improves balancing (apart from levelscaling);
add 1 if some of the most pressing bugs and annoyances are fixed.
Levelscaling: way better than Oblivion, but still very annoying
Quests: high quality, with surprisingly few bugs; radiant quests feel boring after a while
Lore, immersion and realism: good job, although lore still fades in comparison with Morrowind
Story: good for a 2011 game, mediocre in comparison to Morrowind
Balancing: not good, but not Oblivion-style bad
Bugs and design flaws: few serious bugs; lack of player-owned containers at the beginning of the game
Patching: wish this could be handled more reasonably (not to say professionally)
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First let me say that the claims of Skyrim being linear or being small are somewhat exaggerated, to say the least. I have spent 130 hours in Skyrim (on one character) before finishing the mainquest, and it were not exactly 130 hours of boring grind. While the radiant quests tend to get tiresome after the first five or so, there is still much to do in the land of snow and dragonfire. This is not Fallout 3.
Levelscaling
The first section of this review is about levelscaling. If you are comfortable with the idea that roughly 80% of your ingame enemies are levelscaled, and not in the Morrowind way of levelscaling, then you can just skip this section - most likely, you will not consider any of the points I make interesting.
I didn't have much hope that Bethesda would abandon levelscaling to begin with - "never change a running system" is too much of a dogma in software development. I had hopes that it would end up better than Oblivion's and maybe even better than Fallout 3's levelscaling. It did end up better than Oblivion's one: there are no literal bandits in daedric armor, and there is no sudden onslaught of enemies immune to normal weapons (in fact, there are no enemies immunte to normal weapons anymore - this is, I think, an improvement over Oblivion and Morrowind). Still, most of Skyrim is levelscaled, and you will notice it even if you don't look for it. Some places in Skyrim don't seem to spawn enemies at all when the player is really low-level. It happened to me at least once that I was forced to go to an already discovered place using Fast Travel, because the only way to it suddenly started spawning witches. These witches became cannon fodder on higher levels, but the very fact that at some level I couldn't reach a point by foot but could fast travel to it is rather immersion-breaking (fast travel isn't supposed to be a teleportation spell - it is supposed to be an abstraction for travelling by foot!). More importantly, the very idea that you don't gain an advantage by levelling up took a lot of excitement from my game. Why train skills if it will benefit my enemies just as much as me? Leveling up felt like running on the spot, and sometimes even falling back. It did get better around level 25, when I finally was able to handle most of the enemies the game threw at me in the wilderness (not in caves). It got better as I leveled further, since most leveled lists end at a certain point (I think only bosses level beyound player level 50) and since smithing and alchemy are two very useful skills to have at 100 (smithing for dragon armor; alchemy for resistance potions). But if I ever feel like replaying Skyrim with a new character, I might just as well get it to level 20 by console at first, because the game isn't fun if one is not making progress.
Due to levelscaling, Skyrim neither has any real comfort zones (regions where you are pretty much safe unless you are a level-3 character or walk into caves; the Ascadian Isles were such a zone in Morrowind) nor real danger zones (regions one should avoid unless well-skilled and well-prepared; "you don't just walk into Mordor"). While the snowy regions of Skyrim seem to be slightly more dangerous than the Whiterun-Helgen-Falkreath area, and the Reach is harder than both of these (due to being a war zone), it is hard to notice the differences, and all of these zones gradually become harder as you level. On higher levels you will confront frost trolls on the way from Riverwood to Bleak Falls Barrow. Whether you are seeking adventure in the mountains around Winterhold, or trying to have a relaxing walk in the vicinity of Riverwood, the game will often throw the same kind of enemies at you, as if monsters could fast travel. This makes the different geographical regions of Skyrim feel more equal than they should. In Morrowind, I could rather reliably guess a region by the first 10 leveled monsters that I would encounter there. In Skyrim, I can't; instead, I can roughly guess the level of the player character.
This said, Bethesda did avoid the one big mistake they made in Oblivion: the attribute multipliers. They took the Alexandrian solution: drop the attributes. I am not missing them at all. Some claim that without attributes, Skyrim isn't a real RPG, but I prefer this solution to Oblivion's contra-intuitive and immersion-breaking hunt for +5 multipliers. Of course, abolishing levelscaling would be a better fix to this (the only reason to hunt for those +5's is to get stronger faster than your enemies; if the enemies don't level, it doesn't really matter how fast you improve).
Sidenote: If someone is planning a mod that removes levelscaling (like OOO for Oblivion), I am available for comments, testing and/or enemy placing.
Quests
I haven't finished all major questlines, but I have done the mainquest and the Winterhold college. What I have seen so far speaks for Bethesda: They have learnt to make quests interesting, complex (lots of interaction, complex decision trees, nontrivial AI) and relatively bugfree at the same time. Yes, I am aware of https://unofficialskyrimpatch.16bugs.com/projects/7078/bugs, but only a few serious plotstoppers that are not easy to avoid or to fix by the console.
The lack of consequences of "The Forsworn Conspiracy" and "No One Escapes Cidhna Mine" was somewhat disappointing, but then again I have no idea what kind of consequences these quests could reasonably have without ruining the player's gameplay comfort. After all, a burned-down Markarth and half the shopekeepers murdered would make most players just reload an earlier save. The two quests themselves are well-done and build up tension very well.
The randomized "radiant" quests felt nice for a while, but quickly became boring. But one should keep in mind that Morrowind had a lot of handmade fed-ex quests that were no less trivial than these randomized ones. This is a case of "don't want it, don't do it"; there are enough other quests in Skyrim.
Lore, immersion and realism
Where not spoiled by levelscaling and poor balancing, Skyrim's world feels rather immersive - certainly more so than Oblivion's. Several places show the developers' care for realism. In contrast to Morrowind, where Dwemer machinery felt like an affront to physics and conservation of energy, this time we see where these Dwemer constructs come out from and how they are are powered by soul gems. Wolves hunt in packs and show actual flock behaviour. Bandits don't let themselves get killed off one by one. While Morrowind felt immersive in part because the player's fantasy was forced to interpolate many things that the game failed to give, Skyrim feels immersive because the developers actually built in all of these things. Skyrim is as concrete as Morrowind was abstract.
There are several things, though, that keep Skyrim from reaching Morrowind's level of immersion. Most importantly, Skyrim might have 10 times as much new lore as Oblivion had, but this is still 1/10th of Morrowind's lore. There are also too many Nordic clichées for this new lore to be actually that new. Then, there are a few failures that somehow slipped under the QA radar:
- The lore and tradition of the Forsworn is hinted at, but completely undetailed. You get an "Armor of the Old Gods", but you aren't even told the names of these gods, let alone how they are worshipped. They live in neat huts and use badass necromancy to keep their briarhearts alive, but other than that, you have no idea who they are.
- There is some confusion about the Nordic barrows: part of the game seems to consider them remnants of an ancient past (there is a loadscreen saying that Draugr are former dragon servants), another part considers them recent burials (there are two quests involving somebody trying to clear a burial of his own family from monsters).
Also, Sovngarde could be bigger and the people there could have something more meaningful to say.
Still, it is a giant step forward from Oblivion and provides for an immersive game experience.
Story
If you compare the Oblivion main quest with Skyrim's one, you will notice that both follow a similar pattern:
(1) Encounter your main enemy (in Oblivion, the Mythic Dawn, personified by the assassin in the tutorial; in Skyrim, Alduin himself in the tutorial), thus setting the end goal of the game.
(2) Get accustomed and prove yourself to your allies (in Oblivion, the Blades; in Skyrim, the Blades and the Greybeards).
(3) Infiltrate your enemy (in Oblivion, the Mythic Dawn; in Skyrim, the Thalmor Embassy). Skyrim slightly deviates from this, as the infiltration quest shows that the Thalmor don't have that much to do with the dragons; this wasn't clear from the beginning.
(4) Open (but not final) confrontations with the enemy, alternating with fetch-the-artefact quests. (In Oblivion, you fight at Bruma; in Skyrim, you fight Alduin at the Throat of the World. The fetch-an-artefact quests are obvious in both cases.) This should build up tension, but there is always the danger that making this part too long and repetitive ruins the very same tension.
(5) Build an alliance against the enemy by means of negotiations.
(6) Follow the enemy into his lair (Paradise in Oblivion; Skuldafn in Skyrim). This part is usually supposed to have the second hardest fights of the game; this is averted in Bethesda games by levelscaling and bad balancing, though.
(7) The final battle (not in the enemy's lair, but in a place he is attacking/occupying - for better dramatic effect). Normally the hardest one, too, until the DLC's come up with even stronger monsters. In the cases of Oblivion and Skyrim, not so much.
Both games follow this formal plotline without too many twists. However, Skyrim is much better at "filling the blanks" with reasonable content, whereas Oblivion filled lots of them with kitsch (Martin's speeches, but not only them) and tedium (just think of the Oblivion gates, all looking the same and having the same enemies). Storywise, Skyrim is much like Oblivion done right.
The Winterhold College is nothing extraordinary either, but again done without the mistakes of Oblivion's Mages Guild (endless dungeoneering before the final anticlimactic confrontation).
I probably would not enjoy reading any part (or the whole) of the Skyrim story as a book. But I did enjoy playing it as a game: it is a good video game story. We had better ones back in the early 2000's (Morrowind comes into my mind, or rather says Hi from the depths of it), but it doesn't fall behind the game narratives we have in the early 2010's (as far as I can see).
Balancing
Balancing a levelscaled game is extremely difficult. I pity the developers who had to do it. In a non-levelscaled game, you basically decide how strong a character must be to survive in a certain place, and place monsters accordingly (of course, deciding is the hard part); in a levelscaled one, you have to take into account all possible levels of the player. I wasn't surprised to find some oversights on Bethesda's part here. Fortunately there are not that many of them.
https://unofficialskyrimpatch.16bugs.com/projects/7078/bugs/208614 is the most glaring oversight - nothing beats being trapped in a dungeon that can only be exited by beating the final boss, and finding out that you can make basically no damage against the final boss while he takes you out in 2-3 shots. Is this intentional? Doubt so. Sigdis is one of 3 brothers, and the 2 remaining ones are very doable with the appropriate tactics.
Destruction magic has the funny property of being too strong when cast by enemies and way too weak when used by the player himself. If you want to survive a fight against spellcasters, you have to either spam health and resistance potions, or buy resistance-enchanted items (armor/amulets/rings). On high levels, you will have to do both. Casting spells seems useless, since destruction damage doesn't scale well (but your enemies do) and the useful spells take an eternity to power up, and particularly in the presence of shock-casting mages depleting your magicka. I would expect these difficulties when fighting a boss in a necromancer dungeon, but it turns out that random radiant vampires (alone, not in packs) I meet on the road on level 48 are in no way easier. Be they Volkihar, they are not supposed to be harder than Alduin in Sovngarde, are they?
Bugs and design flaws
If you belong to the "not buying Bethesda products until the second patch" faction, rest assured: Skyrim in version 1.1 (that's the day-one patch) was't as buggy as Morrowind with its latest official patch. And it got slightly better in 1.3, although they haven't even started to patch the ESM file (the source of most problems). And that despite the complexity of Skyrim's quests and AI would allow for 10 times as many bugs. Yes, Bethesda has learnt a lot since Oblivion. Besides many minor bugs that didn't seriously hurt my game experience, I had a https://unofficialskyrimpatch.16bugs.com/projects/7078/bugs/209221 and occasionally https://unofficialskyrimpatch.16bugs.com/projects/7078/bugs/208442. Both of these were averted by saving and reloading. I know of very few bugs that aren't immediately obvious when encountered. Save often and you will be mostly safe.
Now for the other kind of bugs - the ones that are not bugs but features. Obviously this is a very subjective category. My favorite issue of this kind is levelscaling, as detailed above. The second design flaw, in my opinion, is the absence of a container where the player can put his stuff in at the beginning of the game, before one has bought the Whiterun house (or any other house, which isn't much easier). This forces the player to collect his stuff on some corpse and return to it regularly so as to make sure it doesn't respawn. Not a particularly well-documented method (I just knew it from Oblivion) and not quite immersive either, but necessary, since on level 5 you have no idea which of the items in your pockets are important, which are replaceable, and which are useless vendor trash. As a dev who knows exactly what kind of stuff is needed where, you might not understand a level-5 player's troubles deciding between a mace and a greatsword; but I don't think the game would become significantly less challenging simply by giving the player some places to store stuff in. Why not give Gerdur or Alvor (depending on which side the player takes during the tutorial) a chest in their house for the player to put items in? The chest might be limited to a weight of 600, to still make buying a house lucrative.
Patching
Everybody knows this well-enough, so I'll be brief.
(1) The ninja DRM patch was pointless. People downloading a pirated Skyrim don't get any problems from that; the unprotected EXE is already in the wild. Cracker teams get a pair of EXE files: protected and unprotected; this makes for a nice research objective. Legitimate players can no longer use the LAA patch (now officially done - good, but late). The only piracy it prevents is the kind of piracy where somebody just copies over his game folder to somebody else. But this isn't much of a problem either, since the unprotected EXE is everywhere on the net. And why it is everywhere on the net brings us to...
(2) The 1.2 patch. I understand that whenever you patch software, some new bugs are introduced and not found in QA. That's normal. But a week is too long a time to react. You could have just offered the 1.1 version as a downgrade to annoyed players. Think of it this way: Each day means more people downgrading, sharing the old EXE file on the internet (often even the one before the DRM patch), and writing bad reviews. Add to this the fact that not many of the issues fixed in 1.2 were genuinely relevant to PC players, so it was more of a service to console players, and the outcome is evident. Achievement Unlocked: Major [censored]storm.
It seems that patching has changed course to a more reasonable one since 1.3, so I am not letting this lower the review score. That said, I am now backupping my EXE file...
Conclusion
Skyrim is a high-quality game. While levelscaling and flawed balancing are marring my personal experience of it, it has still a lot to offer, particularly to someone not as sensitive to balancing matters as myself. Skyrim is in no way a Morrowind 2.0, but a worthy successor.

) and it also annoys me with New Vegas to a degree.
I was expecting a landscape akin to that which I found on Cyrodil side of the Jerall Mountains in Oblivion. And that's pretty much what I got. But with a pleasing return of Dwemer Ruins... 