MW3 fails to match the innovation of it's previous installments, as well as Treyarch's masterpiece, Black Ops.
Cons:
-Multiplayer maps are too small.
-Multiplayer maps are less intricate and its designs are simplistic. Some of the maps felt like mixtures of older maps, you'll see the same chickens from Karachi, and similar trucks and other props, as well as some buildings and other things.
-Very little new additions to the arsenal, besides some new killstreaks.
-Menu interface, and overall game engine is recycled. Some of the titles and emblems are also recycled.
-Campaign is still exciting but remains linear, and strictly action oriented.
-Guns are still too accurate and do not feel powerful and weighty.
-2-3 bullets are needed to get a kill, while in Black Ops and most other shooters, you need at least 4-5 bullets for a kill.
-Sniping still doesn't take distance into account, you just aim the crosshairs on the target and shoot regardless of how far the target is. You also don't even need to lead the bullet if the target is moving.
Pros:
-Online Strike packages are cool
-They underpowered some killstreaks, and loadouts, and it's tougher to string out a killstreak.
-Campaign mode is best in series, even though it's not original.
I really have nothing else to say, it's all there is to it. I'm only excited for the campaign mode really, I'll continue to play the multiplayer whenever I need a diversion from Battlefield 3, which might not be for a long time.