Really cannot believe this isn’t already in place. What’s the point of allowing someone to leave before a match starts if they aren’t replaced?
Problem: Often times, matches start 3v5 or 4v5, crippling teams. It might not be too bad in team queue, as you stand a chance against PUGs or bad teams if you have really good coordination or voice chat, but solo queue is a different beast. There’s very little coordination possible outside of sweeping commands or what little strategy you can talk through in the minute and a half you have before a match.
Solution: Before the match begins, check if each team has 5 people. If not, delay the start of the match until each team has 5 people by pulling in people from the queue. Matches should not be able to start if one team is missing members.