Well, there's a pretty big problem with this system, that I can see.
Picture this: a group of 4 people have played with each other for a long time, have fun playing together, and just so happen to be good players. With this system, anyone on the other team would just leave the game before it starts, and these innocent people would always just have games that get cut off early due to quitting.
Tl;dr: premades of good people are just going to have 30 second games cuz quitting