I have a few problems with the game but i find the most annoying and worse thing about the game is the maps being so small and compact so every corner you go around there will be either a camper or someone running spraying their gun round corners, or someone will spawn next to you because there are not that many big maps.
Infact the only levels i vaguely like are Express, Slums and Hijacked.
To fix the maps you'd need to include some maps like De-rail (MW2), Array (BLOPS1), Overgrown (COD4), Pipeline (COD4), Wasteland (MW2) and Highrise (Mw2).
Now another big downfall to this game is the ridiculousness of the knife, i mean, its almost freaking impossible to stab someone on this game, and the only way to stab someone apparently is to not have them in screen view. apparently walking up to someone and stabbing them point blank in their face with their character taking up 90% of your screen doesn't class as being stabbed, instead you walk through them and miss and on the killcam you see them stab you after your behind them and they kill you.....WTF much!?
Now then, there are several attachments and guns i find annoying and bullcrap in this game, the most annoying is the Target finder, i mean come on? really? i know lets give the people who cannot aim an attachments that makes it near enough impossible to miss without being a complete retard. Sure you could use cold blooded but its pretty useless.
Then we have the n00b guns that all CoD games have that every shite player in the game seems to want to dry hump if he could get inside the game. the weapons in question, the PDW-57 and MSMC, both n00b guns that every player his dog, his sisters grans aunties brothers pet rabbits mothers sons using, you don't understand how boring it is to enter a match and the ENTIRE team both side is using these guns, they may as well have just removed all other guns and forced you to use these guns as its very rare i don't see someone running around spraying these guns because they are overpowered.
The fact this latest CoD promotes bad players and makes complete retards at this game look pro, this is by far the worse CoD for balanced gameplay, but by far the best Cod for customization and systems, i mean i love the points systems but this game could of been made so much better if treyarch didn't try to crush campers and everything else to make it balanced, instead in doing this it ruined the game and completely forced people to play one tactic, "Spray and pray" or "run and gun". In otherwords theres no other way to play this game propperly without getting creamed by bad spawns, terrible players and rubbish connection. I'm more of a tactical player and i'm not the sort of player who rushes in all guns blazing, i like to slowly advance on the enemy picking spots to hold off for a while before advancing to the next area. Tactical gameplay is removed in this game due to the spawns.
Again another thing that makes this game horrible to play is the constant use of UAV, while in other CoDs this wasn't a problem because you could get Assasin, coldblooded and ghost early on which completely removed the usefulness of UAV, however in this one you have to wait till level 55 before you even get a glimpse of unlocking it and even then guess what? you have to be moving forward for it to actually do anything meaning those of you who want to remain undetected guarding a flag or holding a position giving cover fire in a building can't, so you have two choices, run at the enemy with ghost or without it, either way your going to be seen and killed or just blow up by a betty or claymore (again another overused item in CoD).
I could write a 4 book novel on why this game is such a let down yet it has so much potential for its inovation with the class systems, the use of prestiging guns and things, but sadly ruined by all the things they thought would improve it.