What we have lost is nothing big at all in comparasion to what we have gained.
We got back Enchanting as a skill, Pickpocket was also added, made that feature better. We have Smithing which allows us to create any armor we want giving us a lot of options, we have a perk system that is superior to the previous games level up system and adds more customization options to our characters, we have a radiant quest story that won't always send me to the same dungeon everytime, we have handcrafted dungeons that are fun to explore and rewarding due to the random preset item system not to mention better enemies, we can now Duelwield Weapons and Spells, The Bow is much better with the changes, AI is better no longer Damn Rats or standing like a statue when they hear you move, etc.
In a nutshell it's just RPG elitists that believe an RPG has to be done one way but what they don't realize is that RPG's aren't 100% about stats, it's a system and the system that Skyrim is under is pretty damn good with a whole lot of choices in terms of Roleplaying and just playing the game in general.
Open Lock: Does not make Lockpicking useless, it just gives mages an alternative choice for getting into things. With having to have a certain level to open certain locks (the same way the Open spell has always worked) it actually makes it more balanced than lockpicking. The simple aim and press mechanic of lockpicking makes the Open spell useless, not the other way around.
Attributes: The only reason they caused problems is because of how leveling was handled in the Oblivion. You were forced to min/max if you wanted the right boosts. If you combine attributes with the current "Level up, put X points in any attribute you want" system you get the same effect as the current system, with less balance issues and more options.
Mysticism: The spells matter, the school does not.
Weapon Degradation: Taking cue from your reference to the Fallout series, why not just make it similar to that and fuse it with Skyrim? Make so you have to be at a bench or grind stone to repair, and you need ore/ingots instead of hammers, similar to the improving system.
Spell Creation: Not the same spell with a different name. You find me a single spell in Oblivion that allowed me to absorb Health and Magicka from an enemy at the same time, or a spell that leaves someone weak against a spell type and leaves them Soul Trapped, for an easy follow-up with a damage spell that plays the weakness you just put on them. The combinations and costs needed balancing, but even that isn't too hard to figure out.
Classes: Besides the preset classes, it was an arbitrary name. The problem was the major and minor skills behind it, which was already fixed in Skyrim.
It's easy to say what doesn't work without giving any possible fixes. But it isn't that hard to suggest how things could be fixed either. And that's as good of a jumping off point as any.
Now for the things you listed as added as new improved things, the only things I will dispute are enchanting and pickpocketing. Pickpocket is more or less the same as Oblivion, the only difference is that you can actually improve your chances with it via perks and leveling. Other than that it is more or less the same. It makes much more sense to merge it with another underdeveloped stealth skill (Lockpick) and make room for one that is much more useful. For enchanting, the very fact that a skill was removed and later added back is a very good argument that things are better off fixed than cut.
@nilecroc: It's generally frowned upon to quote a 60 lined post and respond to it with one sentence.
