so far, all the ideas expressed greatly interest me
don't limit the clothes simulation to just capes, though...allow for clothing that isn't modeled onto a character, but placed around the character and let the clothng physics do the rest
randomly generated world that don't suck...something akin to the quality of Nethack's randomly generated worlds or Diablo II's randomly generated dungeons only better and with much more variety. So that not only do you never see the same area twice (unless returning to a previous area in your current game) but you rarely ever see the same buildings, geographical features, ect. This will probably require hundreds or thousands of pre-made pieces to be grouped together (much like how Neverwinter Nights's modules are built) but I would rather see a completely unique and rondomly generated world that can match the quality in at least average man-designed environments.
Detailed physics that pay more attention to weight and force of impact than what's currently available. Not only for characters, but cars and environmental destruction as well.
Fully interactive environments.
Amazing and unique visuals that don't attempt to look realistic unless necessary (racing and sports, etc)
Developers realizing that historical war games suck hard
AI that is never 'scripted' but can provide fluid and engaging experiences
Max Draw Distance
Locked Framerates
Post Processing effects. Some of you hate them. You have bad taste
SMOOTH animation that fluidly links one motion into the other. No more robotic movements and no more sudden jerks into another action. Couple this with animations that still have a minimal 'preload' -- that is, while still linking fluidly into the next action, the movement is performed without much delay
The death of DirectX water. Its current implementation sucks. It's an obvious texture effect on a (99.9% of the time) completely flat surface which ultimately defeats the purpose of even using it. Not asking for the effect to stop being used, just to be used in smarter ways like on surfaces that aren't flat as planes.
I'll think of more later. To be sure
Edit: Better sound design. Having at least 10 different sounds for every action so that every bullet impact, sword clash, or footstep doesn't sound like the one before