Improved Character movement animations - might have missed on this one already, but we'll see..
Larger and more populated cities. - Bigger game world than ever before....
Fewer loading screens- confident this will occur ( not sure that the trailer was a good example of this yet....)
Large improvement in graphic realizations, draw distance etc ( jury still out on this as well )
Cut scenes - used sparingly and not as plot bridges.... things like a longboat coming into the dock, vertibirds rising whenever you use one for fast travel etc. ( a nice touch would be an alternation of two or three different camera view angles so that repeated use did not always look the same...)
Audio files should also be considerably larger, be it dialogue, or soundtrack usage
Weather effects - sun, moon realizations .... Fog, gas clouds, light effects etc..
re-spawning in certain areas with different inhabitants than were encountered before..
I can think of more.. but this will do for now. Fingers crossed!