In skyrim the beast races(argonian,Khajiit) look much better then past TES games. But I always felt that they should feel more uh, beastly. Take the khajiit what if they ran on all fours, jumped higher, and could climb things(which I think should be in TES 6) more efficiently? Or while in battle you hear khajiit enemies roar or snarl like a big cat would do.
Or the Argonian which has a reptilian tail that could be used like a komodo dragon and whip people as an attack, or they could have a custom swim animation where they swim like an alligator, hissing while in combat like a true reptile.
I think one of the big things in the next TES games should be focusing on making the races even more unique then ever.