5 years later, why do 4v5s still exist?
An anti-4v5 system should be a basic feature. Seriously.
Prior to the start of a game, the client should check that everyone is connected. If someone isn't connected, the lobby disbands and they're given an appropriate leaver penalty. If someone disconnects in the loading screen, the game is paused for up to 3 minutes. If they don't return, the game is disbanded and they're given a minimum 1 hour leaver penalty, with harsher penalties for continuous/consecutive repeat offenses a la LeaverBuster. If someone disconnects at any time, the surrender time cap is reduced to 10 minutes until they return.
Why don't we have an anti-4v5 system? For a 5+ year old game, there is no excuse.