Lotsa blockers around, needa implement a kicking system...
I havent did a thorough thinking yet but its something like this

A player will be granted kicking right when:
He deal more than 25% of the dmg among the entire team to 3 or more players and be actively dealing damage for the last 10 minutes

He can only kick a player who has dealt and recieved no damage to 2 or more players in the opposite team for the last 10 seconds

After he proposed to kick the player, at least 1 other person from team must agree for the kick to be valid

After kick that player can no longer join the same team in that map again

This is just a rough idea, conditions for kick and rights can be suggested and improved upon