A kick button would be ok but it could abused. Ive played other games not mmo's
But like mass effect or dungeon defenders where you spend most of ur time queing up because a couple a friends are being funny or want a specific class . And it only needs to happen once to someone who didnt deserve to be kicked for it to be broken. I would stop playing the first time someone did that to me.
I know we can block people. That should actually prevent them from joining a game you are in. If everyone blocked an afker when they met them it would make it more dificult for them to que.