I want the game to be as immersive and possible. With that said, these are my top 5... even if they are a little "pie in the sky."
1) Better AI, much better AI - Schedules were nice, but at base, it was just a way to get NPCs to move. I guess I'm hoping for NPCs to have basic personalities and be reactive to what I'm doing, and what my reputation is. Fresh in town, I'd expect some people to be cautious of me, while others curious and want to talk to me. Depending on my actions, it branches out from there. If I break into someone's house and rob them, and he catches me, he might attack me (if he's the hot-headed courageous type). If I kill him, all should be good. No witnesses, so nobody knows about it... at first. Does anyone else live there and will eventually find the body? Does he have a job or a routine where people will notice his absence and subsequently stop by the house to check on him? Eventually, unless the NPC was a friend-less recluse who never left the house, his death will be discovered. Did anyone witness me enter or exit the house around the time of the suspected murder? I might have to answer for it at some point.
Same scenario, but instead of killing him, I flee. Depending on his personalty, he might pursue me into the streets yelling for guards, or he just may be happy that I'm out of his house and not report a thing.
Different scenario... he might catch me in the act and demand that I leave and relinquish his property (if they're the courageous, yet, pacifist type). He might even say that if I leave, he won't tell anyone about it. Maybe he's telling the truth and I go about my business. Or maybe he's lying and I'm confronted by a couple guards the next day.
He might also take off like Usain Bolt and find the nearest guard (if they're the somewhat cowardly/smart type). It wouldn't be long before I meet said guard.
Maybe nobody is home and I get away with it. Maybe the NPC gets home to find things missing and reports it. Maybe someone saw me around the house and a guard later questions me, inspects my inventory and finds unique items to that NPC and I get busted. Or maybe he finds that I'm only carrying common items so nothing can be proven.
Whatever the scenario for an ordinary robbery, the NPCs could react in numerous ways to it, as well as there being different consequences and outcomes. It would also go without saying that the NPC (if left alive) would not like me, and word would probably get around causing others not to like or trust me... which would have its own consequences. Guards might also be keeping a closer eye on me as well, making further robbery attempts that much more difficult.
That would only go for that town. If I journeyed from Whiterun to Windhelm, no one would think poorly of me there. If someone else has traveled between the towns, then some might have heard about some thief running a muck in Whiterun, but they wouldn't know that it was me. Well, unless that traveler happens to be there and points me out
Maybe some of those people will then be leery of me, but not necessarily dislike me since they're only allegations, and I haven't done anything bad in Whiterun.
I didn't intend to go off on this wild tangent, but things could be extremely immersive if your actions have dynamic and lasting reactions. Anything like the above is most likely doubtful, pie in the sky, but I could dream for a more living, breathing virtual world.
2) Incredible sound design - I'm firmly in the camp that audio can make or break the goodness of a game. When I was little, I saw The Shining (bad idea for an 8-year old, unless you want reoccurring nightmares for months to come and an instant fear of the dark). I watched it a couple years after that, and it was still scary. I watched it again later with the sound down, and it wasn't scary at all to me like that. Think of any horror film with no sound, even Jaws. It svcks a good chunk of the emotional response right out of it. My point is that audio compliments the visual, and both are needed to pull you in. If one area is lacking, it fails.
After watching the latest videos from GI about the sound design, I'm excited. Like usual, it appears they're putting great effort into detail, and I couldn't be more pleased.
3) Localized damage - If I beat someone on the foot with a club 10 times, they shouldn't die. If anything, they should limp, and their mobility should be greatly effected. If I slash away at someone's arm to the point of serious damage, they should drop their weapon, then either switch to their other arm and continue fighting, or take their losses and book it the heck out of there. 1-shot kills should be very possible, even on higher level enemies. Although, higher level enemies are higher level for a reason. They should be more skilled in combat, therefore, do a much better job of defending their vitals from 1-shot kills.
4) Deformable stuff - Probably won't happen, but it would be nice to chop down trees, for example. Not that I'm longing to chop down trees, I just would like the ability to destroy stuff in the world Or even see the dented effects on your armor from blunt weapons, scratches and gouges from blades, or singes from fire. Etc., etc., so on and so forth.
5) Believably realistic environments - This is a pretty big bucket here, but in the bucket are more realistic lighting (particularly at night and in dark locations), seasonal changes, impressive looking rain and snow, how the trees move, and picturesque scenery. I'm sure that there's sunny blue skies on some days in Skyrim, or a crackling fire at a snow-speckled camp site at dusk. Something that would inspire me to take 1,500 screen shots to cycle as wallpaper.
So those are the top 5 things I hope for. I've seen glimpses of each in various games, but never all in the same game. One day... one day