My main issues with it are pretty much all about riot shielding since that's all I've really been using so far, but I have a few others:
-spawns suck
-maps are okay, they're just like...ALL close quarters and it's pretty annoying have the same basic map over and over again, I loved mid ranged maps in MW2. I was really looking forward to the maps in this game since infinity ward's maps, aside from this game, are like mostly amazing.
-akimbo fmgs are ****ing stupid as hell
Yeah, but the riot shield ****ing sucks in this game. Like, I was really looking forward to all of the riot shield glitches and desynchs being fixed in this game since they should have learned from MW2, but like...it's even worse. I've been knifed/shot through my riot shield so many times it's dumb, the slightest movement to the left/right parts of your body get uncovered, when I lunge at people with the riot shield I get like...teleported some of the time where I'm not even facing the right direction of where I did when I lunged, A LOT of times I don't get hitmakers on people when I CLEARLY hit them, I have no idea wtf they were thinking making stuns as slow as flashes throwing, now I have to waste a 2nd perk for quickdraw pro since you can't do much without it, I don't know what they were thinking making it so you can get stunned from a stun grenade in front of your riot shield so even when I do stun someone I get stunned by my own grenade most of the time and i get killed from somewhere else before I have time to kill the guy and I can't even use blast shield pro which would have fixed that since quick draw pro is a must have, not to mention that stun grenades get you desynched easily (by desynched I mean you're already back with the shield in front of you on your screen, but not on the killcam), semtexs kill you when stuck on your shield with blast shield on unlike MW2 (not much of a problem, just kinda lame), I don't really know why they put in a faster melee option if you can just melee cancel in this game anyway seems like a waste much would have preferred melee riot shields did something like commando since commando in MW2 was really only a problem with knifing.
Things that I've liked for the riot shield:
-stun grenade direct impact combined with the stun stunning them can give you a 1 hit kill with riot shields sometime
-there was something else here, but i forget.
But yeah like seriously, if you were going to put a unique feature back into the game that already was like low tier before, you can AT LEAST fix some of the glitches that were in the previous game instead of making them worse.