I know I'm not the only one who has said or thought of this....and certainly Activision has given the idea some thought.
Why not create a Call of Duty: Greatest Hits- Mulitplayer Edition? Basically, it would take the "fan favorited" multiplayer maps from every COD game and put it in one playable game. Take the favorited weapons, perks, equipment, streaks, from all the games and put it all in one game.
IMO, the Black Ops 2 game encompases more of the most balanced gameplay when it comes to how scorestreaks are rewarded, the weapons, the perks, the point class system, and basically every option in loadouts that are possible. Besides how you can create your own emblems like no other COD has done in the series.
I think a Greatest Hits game would sell like crazy! Imagine being able to play all your favorite multiplayer maps from all the CODS in one game!
Treyarch would need to be the lead team on this project!! Please Treyarch and Activision....make this a reality!!!