People had been complaining (and rightly so) about players queuing up and then going AFK for extended periods, players who were queuing up as roles they had no intention to fill, and (the biggest complaint) about players that would use the random dungeon finder to try to get in one that was the daily. If they could manage to use random AND get the right one, they would get the bonus for the random and get the completion for the daily at the same time. To accomplish this, these people would queue and drop group over and over until they got the dungeon they wanted. I think these were the main reasons the timer was implemented, and it was implemented as a way to discourage that type of behavior. I think it was also implemented as a way to discourage other bad behavior that people were experiencing in groups, such as extreme rudeness. That is what the 15 minute "punishment" was supposed to be for.

However, a kick system like this will probably never be made to be 100% fair. The game can't tell if someone was kicked for a valid reason, or if they were kicked because the other 3 people simply felt like kicking someone. They could implement a check box where you could check the reason for the kick, but people will abuse that too.

I wish there was a way to make this kind of system work perfectly and fairly, but I really don't think there is a way.