Why not implement a system such as the one in Dota 2?
I will explain for those that are not aware.
In Dota 2 if you leave a match you are placed in a low priority que. Where you are forced to play a certain gamemode with other people in the low priority que.
If you leave this low priority que, you will receive more low priority games
These matches take a significantly longer period of time to find, and nobody wants to be in them.
However, this is not my main point.
In Dota 2, there is no surrender system in place, not when I was playing any way.
However, if someone willingly leaves or disconnects from the game. Other players are safe to leave the game without a a point or low priority que penalty
Meaning, say for example, Ashe leaves the match in a ranked game. Its a bummer, she isnt coming back, its a 4 vs 5 with no adc and essentially a waste of time. Not saying that it is not winnable, but nobody wants to waste their time on a match like this.
In game if Ashe is gone for more than 5 minutes, the game becomes safe to leave for the other players to exit , Ashe being the only one that receives a penalty.
sure, you may say that players duo que in ranked, and can abuse this system by just leaving other team mates out to dry.
But i believe that it is one of the best solutions to a very large problem that the community faces on a consistent basis.
Sure a duo que might abuse it, but there are three other players on each team.