The majority of dominion games seem to put me in games that are already in progress on the losing team because someone dropped out. It kinda sucks when you're losing games because you entered a hopeless situation. This seems to happen less frequently in elimination, but it still happens. You already have it so that leavers get a bot substitute, it's not like the game isn't functioning without the newcomer anyway. In fact there have been several times when I screwed over a teammate just by joining because they were reviving the bot that I replaced when I came in.

On top of that, while waiting for the next game to start the majority of people leave and the 3 or 4 that wanted to stay end up leaving or getting kicked out because nobody ever came or will come to fill those empty slots. If you prioritized these lobbies then we get to stay in lobbies we like while the newcomers won't get stuck on a pointless struggle.