It would be cool to introduce new weapons, instead of glass, obsidian, (just an example) but still have some originals like steel, elven, ect.
Anyone hear of the Dark Brotherhood return? It would be VERY sweet if they made a new return, possibly with some new techniques you could only learn from them, as well as a better story for it.
Hopefully Alchemy will return better, bigger, more expansive and as crazy as ever. im a plant person so if Alchemy is not in Skyrim, ill be honest, i might reconsider buying it. the Elder scrolls series isnt TES without alchemy.
It would be cool to possibly get married as a side quest and have children (not to copy the Fable series) but have one of the sie quest or random encounters be when you get home you see a note on the table saying you need to give X amount of gold to (random dungeon/cave/ house you havent been to yet) and save her.
Mounts would be nice to have a return but have mount attacks, wither archery on horseback or sword or spell. i hated how i couldnt attack and had to get off my hourse whilest being chase randomly about the forest by cave trolls. at least if mounts return, let them do something other than just be there to look pretty and be a ride.
I didnt like how in Oblivion, if you stole something and someone saw it youd instantly have a bounty and guards could somehow magically appear/know where you are, what you did, without the guy even telling the guard he saw me steal. i think it would be cool to have a system where if someone sees me try to steal, they would try to get it back by asking for it back or if they are more aggresive, attack me to get it back. if i attack back, then he can go run to the guards and say this guys stabbed me and took this ect. ect. then youd have a bounty and people would be after you. It seems to make sense. You dont see a kid go into a store to steal candy, see him do it, and then magically a cop car comes just because you witnessed this kid take a 5 cent candy. One more step toward realism Bethesta ;]
More to come... this is just off the top of my head, the list will continue, any thoughts?