It would be nice, if a player joins your raid boss and sabotage's it you should be able to kick that player. If it's your raid boss, you should have more control!
It's already been discussed and we all know it's a BIG problem but currently the devs are saying this cannot be put into practise.
I think you just have to be very careful with who you invite in and don't push to fill the lower level spots if you don't need to. Which you often don't.
These raid bosses here are a disappointment. II'm on one boss where seventeen people haven't healed. Of course the boss isn't going to make it. Whats really sad is these are all high levels. There needs to be some changes. I think after a day of no attacking or healing on a boss the games kicks you off.
Problem with that is some people may do a significant amount of damage and the respective heals on the first day before leaving finishing the boss to the other 29 players. They wouldn't deserve to be kicked off.