You should have acted. They're already here. The Elder Scrolls told of their return. Their defeat was merely delay until the time after Oblivion opened, when the sons of Skyrim would spill their own blood. But... there is one they fear. In their tongue he is Dovahkiin; Dragon Born!
Improvements: Graphics, Physics, AI, Combat seems alot more visceral and interesting, Superflous Class system so that you can naturally grow your character then being constrained to some predetermined skills.
Dumbing Down:
Out of the box magic is really limited and frankly poor by RPG standards set in the past,
Complete ripping apart of the alchemy,
removal of certain skills like without athletics/acrobatics there is no way to increase running speed or jump height,
Removal of attributes so that we cannot make our character stronger in certain ways rather it makes broader changes to your character and removes a element of roleplaying,
Handholding... you can't fail any quest, theres no disadvantages for joining a faction (so you're not making enemies ect), you make little to no impact on the world so its not dynamic in any way, conversations are heavily reduced so that alot of the depth is gone, and the puzzles are alot simpler then they have been in the past.
The biggest for me though is the handholding for how you get around... in the past NPC's would give you directions on how to get where you need to go punctuated by land marks or road signs and you'd have to use your knowledge of the world to make your way there.
So Skyrims (and oblivions) quest markers and even a quest arrow on the hud ruining alot of the immersion by essentially giving you a medieval GPS device.
I suppose I should mention the blocky user interface but that can easily be fixed so let the real problems speak for themselves.