in no particular order:
1 first person all the time (no third person kill cam, werewolves or horses)
2 better fort battles......maybe i was spoiled with my 250 npcs mount and blade battles on my 4 year old PC but the 16 or so npc battles in skyrim were just pathetic. soldiers would magically just appear right in front of you for no reason.
3 scaling destruction spells (this isnt necessarily about the issue with spells scaling so much as it is that i prefer using flame and sparks because chain lightning and fireball hit my followers all the time, id like to see a higher damage flames spell with a higher mana cost)
4 adjusted crafting rates......im all for slow leveling but alchemy is really really hard to level meanwhile smithing and enchanting are really easy to level. using just normal rates of finding stuff while adventuring and crafting it when i get to a town to sell, im always close to or over 90 by the time im level 30.
5 more summons. what happened to my daedroth, clannfears etc?