Honestly, I think this game is awesome; 80% of the time it's a lot of fun. But the people that are just playing the game to troll makes for an extremely frustrating experience. I played a match a few days ago where someone purposely TK'd me with a truck, and then talked shit to me the entire rest of the round. There was no way to mute them, so the only other option is to leave the server; with a total of 600 or so players on the East Coast, that's really disappointing. PLEASE give us the option to mute players. And implementing a TK penalty, where 3-5 TKs removes that player from the server, would help tremendously.
I'm not sure if you don't want to kick people because you think that will discourage them from playing altogether or something, but the trade-off is you're making the people who want to play as a team leave the server because their match is being ruined by someone who is not playing the objective. Even if the TKs are accidental, if someone has five TKs in a round and gets kicked, that would make it pretty obvious that they need to learn to recognize their team's uniform/attire. And I'll be honest, accidental TKs don't bother me at all; I understand when someone is a lower level and doesn't have a lot of time in the game, and even Veterans make mistakes from time-to-time, but the people who are trolling are ruining the game.
Why is there no Report System? After a player receives a certain number of reports (for TKing, or even toxic behavior), you could at least check their stats and see if there's a TKing trend. If a player has a dozen Toxic Behavior reports, that should indicate that player isn't there to be a good teammate. In a team-based FPS title, where friendly fire is always on, there HAS to be some sort of system to keep TKing players in check. If not, you're going to lose the players who are there to build the game and community up, instead of tear it down like the trolls love doing. After a match of being forced to deal with trolling, or having to leave the server, I quickly decide there are a lot of other games to play instead.
P.S. I would also suggest removing the ability to TK teammates before matches start. Even though the deaths don't count, people still get upset, and will often TK the person who shot them during pre-match. It certainly doesn't encourage a team-mentality, either.