Anyways...
-good Writers are comparatively cheap. But for this game we actually want them. The vast majority of skyrim seemed to be written by a 10 year old and the game's Ai would have done a better job.
-Animations are more important because of combat advances , Storytelling, acrobatics, more complex terrain, character believability etc . Animation would be expensive. A great animation system probably isn't so much but when you consider how many Human animations would be wanted and how many of them might have skills or conditions that should change the way they look
-We'd want the Ai to be Smarter than something from doom. We'd also like more at a time.
- The Intellectualy inept that the Series has Targeted for the last two games will of course want better graphixors. Furthermore The rest of us would also Like better graphics (but care more about other things) A colour shader or switching Bump/alpha/hight maps Would also allow for A lot more Variety in stuff with less effort..
Cloth physics
Nice lighting
Good particle effects
Post proccessing
Proper fur/hair.
Better water
Tesselated stuff
Textures that get wet/dry/burnt
Roots from trees and rough rocks
Destructible Stuff would please many people. Although it's not seen as neccessary for Tes. Eventualy however it might Be!
Many of us would like bigger cities. Not all. It would be Nice to have "cities" be more than simple quest hubs. Furthermore large cities would be good for both criminal players and Social players who roleplay merchants/buisnessmen. It would do the lore some good too as it would more accurately display Demographics (race,magic use, Profession.. because in the last few games Most of the population consisted of magic using bandits.) Furthermore it would allow each guild/organisation/church to put a guild hall or safe-house or similar structure Into every City without appearing cramped. It's assumable that common housing could have procedurally generated/fairly sparse interiors without considerable backlash to save money. Even then it would be more expensive to get cities of that size. Bigger Cities would also mean Bigger Land, Bigger land means that only small areas should be hand-crafted and Procedural generation algorithms should be improved.
Valenwood would require giant Trees ( redwoods Being considered Small- There are entire cities on Top of some trees) and Moving giant trees (not Ent's with arms and legs . Probably more like an octopus with large roots gliding along the ground) Which would Probably be amongst the most Difficult thing a game can do.
Oh yes. We'd all like the game playtested for Enjoyment as well as bugs. It clearly hasn't happened much recently and it's a huge flaw. Play testing for fun is the reason why Valve did so well with half life (which went through a lot of revisions)