-more depth,moral choices with tangible consequences (even "simple logical things" - like if i wear a Forsworn armour i want all the guards attacking me - and the opposite of course)
- optional hardcoe mode (with all Npcs killable after "they've done their job" or replaced by someone else)
-karma/reputation and the opportunity to join every faction - but with consequences,you can't join Forsworns and Stormcloacks/Empire at the same time without problems -or the companions and the Db,Thalmor and Empire etc..
-better animations,better wildlife creatures,mounted combat,more weapons (spears above all)
- more challenging dungeons/puzzles
-physical variety - with all due respect i don't think all the "old ladies" have a pin up body like in Skyrim

-more "advlt" contents (like Red Dead Redemption ; i miss the opportunity to catch a prisoner and send him to jail instead of killing everyone i.e.)
In hardcoe mode:
- balanced rewards; if i commit an homicide of an "innocent" -and discovered -i must pay at least 20000-50000 septim, lose some ability spending long time in jail or living permanently as a criminal paying the consequences of my action
- a time limit with aging - this would be the real challenge,with a more reliable and adaptable time scale of course