-You can stomp teammates when they are down. This means if two players die on top of each other, it is random chance if you stomp the enemy or teammate. Sometimes you can't wait because the other player is a medic who may have self-revive.
-Sliding knocks down teammates, this gets really annoying, very quickly. Players love to randomly slide so chances are half your team will get knocked down on the way out of the spawn. On top of this sliding is a key maneuver that you need to be able to do. Furthermore there are spots where you automatically slide if you are using SMART run. I hate getting knocked down by teammates 3-4 times on the way to the battle.
-The friendly fire XP penalties are way out of whack. They feel incredibly front loaded. Clipping a guy with a few bullets when he steps into your line of fire usually dings you for 15-25 points. Continuing to dump your clip into him doesn't make it that much worse. Winging a teammate should carry a light penalty that ramps up as you deal more damage. The heavy penalty should be if you down a teammate.
-The server browser has no indication of what settings the servers run. You have no way of avoiding friendly fire servers without joining them and then leaving. You have no way of filtering them out.
-Mines have huge FF penalties, if someone gets FFed by a mine it is their own fault. They knew that mine was there.
-Grenades carry some heavy FF penalties too, if you hit 2-3 enemies and 1 ally, that was, overall a good use of a grenade. The penalty shouldn't be large unless you hit multiple allies.