2) EMP Grenades - They are too good, and too strong, and they favor camping groups who can then chuck / spam them at building entrances pinning you in, or environments, completely cutting off navigation of the map. They also are too large in Area of Effect going all the way through a multilevel building from the ground up. EMP grenades are also kind of cheap in objective game types due to the ability to throw them at sites and then attack with a defenseless opposition.
3) Weapon balance is an Art and Science, and even better developers like Bungie have struggled to "master" it, so I'm of the firm belief that this game has been balanced to favor the vanilla version which compensates for the Auto Armor perk. When playing without Auto A, and not having Armor On, the game starts to feel like CoD in players' ability to kill across the map perched in buildings shooting from windows. Scar becomes a deadly Sniper. And most other weapons appear to be OP without AA, which then makes a game of people using Armor All the time, rather then turning it on pre-engagment. In Crysis 2, one didn't have to have their Armor ON when crossing a battlefield, they were able to run in power mode knowing that it wasn't going to be easy to kill across the map with semi autos, and burst fired rifles. Then there was the superior cloak which allowed flanking. This game feels too much like it favors camping, as a result of an inability to flank without being dropped by Scar and Takedowns / Grendels.
4) Surveillance 3 is a bugged perk - using it to not be tagged, is the main reason for its use in a competitive game. But it breaks the usual hit-detection causing point blank shots not to be registered. More on this soon (a Video of Proof). There seems to be delay in how the shot is registered. The module is giving you an "X" where a hit marker would appear, when you see the killcams after being killed by an enemy that you should have killed (that was also wearing Sur3), you'll notice that they took no damage.
5) Team Spawning is game breaking. You are either spawning with your team and rushing towards the enemies spawn, or you are being spawned trapped. The game doesn't do a good job of determining hostile presence and spawning at more favorable location. Also with 5-7 seconds of delay between spawn, you often be spawn killed while still selecting a new loadout
6) Splash Damage too large causing Cloak Glowing Effect too far from explosives. Cloak has been significantly nerfed in Crysis 3, but the worst thing is trying to snipe and being made visible by a grenade 50 yards away. For Example: I'm on the Tower of Hell's Kitchen glowing from grenades thrown at the ground below. It doesn't make sense.