Most on your list has been discussed already. They wont implement 4-player fights now, but in-game voice chat will.
ok, lets see....
- Maybe a optional 4 players at a time feature (because that'll be funny)
- Being able to communicate with headsets while in a game lobby (of course with a mute feature because of the occasional troll)
- Some more beautiful shaders (im sure some will disagree with this idea because some of their systems may not be able to handle the 'higher end graphics.')
- And what ever else comes to mind (feel free to add to this list)