Best COD ever was COD 2 on PC. Nothing has even came close to that. However, I think this game has a lot of potential. The biggest problem with this game is the maps. In my opinion, these maps are the worst set of maps I've ever played on in any game, ever.
But, this is coming from someone who avoided NukeTown in Black Ops 1. I thought all the other maps in that game were brilliant. When I first started playing Nuketown, I thought it was just a map they threw together for fun to test the game on..and then decided to go ahead and release it.
I would have never guessed that people would have hosted tournaments on it, and took it seriously during online play.
Now, in black ops 2, they have made all of the maps in this game based on Nuketown..I mean Hijacked, is basically an even smaller, even more cramped and laggier version..
If they would make maps like Summit, Firing Range, etc along with fixing the matchmaking...the other problems like SMGs, Shotguns, etc would sort themselves out.
TL;DR - The problem with this game is the maps.