I don't mind the reach system
I would love black armour, and gold as well. I think we should be able to put custom designs/emblems on shoulders for example.
Pre-Made maps, definitely. I much prefer playing on Reach's in built maps, not the annoyingly awful custom forge ones. I'm sure it will be the same for Halo 4.
I personally liked the DMR. Might just be me though...
I would like to see a whole bunch of completely new weapons, may increase the longevity of the game.
I rarely encounter team killers anymore. I'm sure everyone has at least once just killed/melee'd someone - because they are in the way/annoying you etc