Why doesn't Treyarch do the same thing they did with black ops 1 and come out with a DLC that's just zombies. It could be counted as that ever so secret 5th DLC that was found in the coding when Black Ops 2 first came out, plus it's just an easy 15 dollars for Treyarch from every person that buys the pack.
The maps can be decided fan wise, they just put a poll up on their website listing all the maps and allowing the users to vote for the 4 (or less) maps that would be included on the pack, or if they wanted to keep it a secret and just come out with the pack just to surprise us and how they would choose the 4 (or less) maps is going back and seeing what their users favorites are.
What they did for Buried, Mob of the Dead and Origins, they gave a new look to the HUD and changed the zombies appearance to the style of the map, they could just do the same for the maps that they chose and it wouldn't take much work considering that all they'd have to do is copy the map over, possibly remaster it (that part may take longer) and whatever else they might want to do with the maps.
This was just an idea I came up with, most of this community was probably thinking the same thing, but I didn't see any forums on it so I decided to make one myself.
Thanks for reading.