I really love Zombies, and I believe they could make a "sub clan" option for Bo2.
Like my clan Elite Force 717 would create a "Zombie clan" linked to the clan called umm "Z-717"
Surviving a certain ammount of rounds would give points for leveling up the SubClan. We could get stuff in the game, like IDK customizable Camos, or some kind of stuff. (depends on how Zombies will work in Bo2)
IDK how it would work atm, but I believe zombies should be part of CoD Elite =]