Nobody comes out ahead in this. The only way withdrawing helps you is if you are the only person in the world who is that lazy, but you'll quickly found out that plenty of other people are just as lazy as you that, ironically, is busy competing for those 2/3 slots. This is compounded by the fact that there is basically no incentive for a tank to leave a 2/3 AK/WP group unless that group is just terrible, so it's actually a pretty high-risk situation for the tank to join a 2/3 (though you should still always take the chance). This is one of those situation where players need to be protected from their own stupidity, but if SE choses to do nothing, it doesn't particularly bother me that someone who can get instant queue is spending 20+ minutes to get into a dungeon that can be finished in under 30 minutes easily.