Matchmaking settings.
I just got the idea, that Riot could create a matchmaking settings to the options, or the party screen. To decide what is more important. A game with main role, and players of similar power, or low qeue timer. 0 on any setting would mean infinite.
We could set up 4 roles instead of two. The first is what you want, and the other 3 would be the. "if i get autofilled priority". The fifth role you don't set is the role you really don't want to play, and you would never be autofilled to that one.
Maximum wait. The maximum qeue time you would like to wait. Once that time limit reached all restrictions removed.
Autofill timer. Time you are willing to wait so you don't get autofilled. Once that qeue time pass the next chosen role gets enabled.
Power over time prioirity. This would set how much the power difference increase in qeue. At start the game would try to get OFFICIALLY similar players. But as time goes on the search get wider. This setting would decide how much time should pass to set the search wider. For example, if you set it to 1 second, then with each second the game seeks wider skill levels. If you set it to 10 minutes, then only after 10 minute the game would increase the skill level, and would take another 10 minutes to increase again.
Smurfs, bought accounts, and boosted players would not get in their level of course, but there is no real way to avert those.
Could this make damn long qeue timers? Yes, but it's your decision. For some people it is important to get into game fast. But for some player time has little relevance. I can just start start Skyrim in background, and don't give a damn, if qeue time takes 20 minutes. As support main i wouldn't be affected much, but i'm sure, that there are players who would prefer to wait more for a good game, than rush into a bad one. And i think, that there are the opposite too. People who want to get into game real fast. No matter the cost.