I personally don't think the obvious choices such as commando, noob tube etc should be taken out, but they should be toned down a lot.
As for what they put in, I'd like to see skins/camos for guns, loads of attachments.
I think a really fun game mode would be:
It seems like regular TDM or FFA but when a certain player gets, say ten deaths without a kill, they turn into a zombie for one life.
Obviously it would be a separate game mode than normal FFA but would still be pretty cool.
I think if they have to have customizeable killstreaks, the streaks should be only 3,5,7 BUT you have two different options. For example, 3: Radar or Jammer, etc etc.