I haven't had a criticism up to this point, but I think I've put enough time in to have a few grievances
1. sluggish controls in PvP, it's just not smooth enough for my taste...it's not terrible, but it could be better
2. shotguns....for me, they're the most useless guns in the game, yet, I get killed by them constantly...not sure why
3. supers......in PvP, the supers are a bit much, I'd LOVE a mode where they were disabled
4. all or none reward system for PvP....came in second place last night, highest scoring game I've had, Syn did better (of course) but I got a lot of kills and captured the f**k out of flags....what did I get...NOTHING. w.t.f? One of the people on our team who spent the game eating dicks, got two rewards. again, wtf?
really, that's it, and it's all PvP based complaints...I LOVE the PvE/Co Op portion of the game. Absolutely love it