The amount of waiting is very excessive. It causes a lot of people to alt tab out from the game and then they miss the first 10~ seconds of the match sometimes. I blame the devs for this more then the players that tab out, because the prematch wait time is ridiculous.

Just quickly display both team's portraits at the same time and then do a 5 second countdown and start the match. There really is no reason for it to take so long.