The videos online have shown quite a bit of the fly-throughs, but none of the combat demo. A lot of this will be editorialized impressions since most everyone has by now read the facts.
Here goes.
ENVIRONMENTS:
The environments were actually very nice. They were not as cartoony as one might expect and there were a lot of subtle details that were pretty thrilling. Things look more-or-less to scale. Morrowind looked very nice, as did Skyrim (some of the detail in Skyrim was breath-taking) and Hammerfell in particular were a treat to see (always been my favorite province). Daggerfall looks pretty generic sadly. Some of the buildings in towns had a touch of the over-sized WoW-like style but not to a point where it was distracting. For the most part the world looked very good and it surprised me how much detail there was. It didn't look as impressive as Guild Wars 2 or Copernicus (RIP), and the landscape and structures were much more subtle and realistic.
Some of the LODs and fog shaders look buggy and unfinished but they have time to polish that up for launch.
CHARACTERS:
This is where it started to fall apart for me. It wasn't the cartoony, disproportionate nature of the characters that irked me, but moreover that they looked very out-of-place in an otherwise good-looking world. They didn't seem to fit and that is a problem in any game regardless of art-style. They weren't cell-shaded, but it was almost as if they were and the environment was not, that's how much they stood out, and in a very bad, distracting way.
The Khajiit and Argonian designs are a joke. You guys have seen pictures and stills but in motion they are even worse. Armor is also not looking good, both stylistically and quality-wise. There are some familiar designs but they seem very bubble-gummed up. Also all the armor and clothing has the same spec-mapping and shaders, but that could be because of the pre-alpha status.
ANIMATIONS:
Animations look off for some of the character models. Some are very smooth and some are very clunky, but that is forgivable at this stage. If the clunky ones catch up to the smooth ones by release it will be passable, although the run/walk animations seem like they are not tailored to the individual character skeletons yet. No major glitches, just no proper inertia and weight distribution: looks floaty and unconnected to the world.
COMBAT:
...is a mess. The main problem is that they're trying to toe the line between action and cool-down combat. They have basically the same system as GW2 but without any weight or connectivity to the character. It was the least impressive part by far. Also, the interface needs work. The one thing I did like was that your health, stamina and mana disappear when you're not using them like Skyrim. However, the lack of interface feedback was a problem and made it seem really messy. Maybe it's better when you're actually playing it but as it was them toeing that line was a major issue. They either need to go full-on WoW-like feedback, or go full-on Skyrim. The in-between is not working for them.
Incidentally, there was another MMO at the show, Neverwinter which was almost identical combat-wise except Neverwinter was more action-oriented and hits/blocks/dodges actually connected, unlike ESO. Also, you do not seem to have to aim your shots in ESO, if you are targeting someone and in range, you will hit.
Still, this is the main issue that makes it not feel like Elder Scrolls. And the indication is you will be doing a lot of combat.
We saw the class-combining and the fireball whirlwind...it was...dumb-looking, that's all I can say about it. It honestly looks like more trouble than its worth.
The real problem combat-wise is the similarity to GW2, Neverwinter and several other big MMOs on the horizon. It isn't straight WoW. But it has nothing in common with Elder Scrolls either and it is definitely not enough to stand out in such a crowded market.
Edit: Finesse system, totally forgot about this. We didn't get much into it, except your skill with it might yield better loot rewards (which I personally find pretty silly) but the closest thing I can think of to compare it to is the combat in the first Witcher game, where if you time your moves properly, you build up power/finesse and that carries over from enemy to enemy. Another thing to compare it to would be a rhythm game like, Guitar Hero I guess, but of course MUCH more subtle.
QUESTING:
We didn't see the player talk to anyone to get a quest. Instead they simply entered an area and the quest appeared on-screen to them. It was automatic. The player wasn't grouped with the other players doing the quest either, but they all seemed to get credit. It was much like a small-scale version of the public quests in Warhammer Online, except inside a public dungeon.
They did then do a time-traveling quest fighting a werewolf lord. It was a little confusing and very very silly. Quest-givers had a glow around them, and there was at least one fetch quest. The only cool part was the choice to kill the werewolf or save a woman. Not sure what repercussions this will have but it was definitely not something you see every day in an MMO. I wonder how many quests will have these kinds of choices.
CLASSES:
Not really enough info to go on but they did talk about wanting classes to not be restrictive and that pretty much any class should be able to fill any or most roles. Sounds to me a lot like TOR's class system but again, not enough info to make any real conclusions about.
CONCLUSION:
If they polish the graphical elements on the character side and redesign some of the character models, then pick a direction for there combat and separate races from factions, things could work out for them. This won't be a WoW-killer, and will probably play second-fiddle to GW2, not unless they make a really bold move with their combat and immersion (although neither of those are really the focus for them). Nothing blew me away and the fact that they didn't win any Game-of-the-Show awards is indicative that the critical reception was luke-warm at best. I spoke to several journalists about it and that was the impression we all got: Meh. Even as one of the biggest Elder Scrolls fans this just did not get me that excited. It was not terrible, although one could say that about some of their design decisions, but it wasn't anything special by any means.
If all you need is the Elder Scrolls lore to enjoy this then more power to you, but if you're looking for the TES feel and/or gameplay, it is all but entirely absent.
Feel free to ask any questions.