Autofill - @RIOT please make it stop.
I don't understand, you had a great system, and now you're just messing it up. I let out a cheer when dynamic queue was introduced. Gone were the days of "Mid or troll", and watching people bicker about call order vs pick order. It was a wonderful day. Now I'm sitting here just watching you mess up all your hard work. Playing normal's while waiting for the season to start, I'm watching lvl 27 accounts get matched up vs. diamond 1 players. What is the point of autofill even existing? How does that even happen?
Here are some steps you could take to fix the problem without making your player base cry.
Autofill - Simply make this a TOGGLE-ABLE option for players. Most of us would rather wait longer to get the roles we wish to play. However if it was toggle-able and you wanted a faster queue time, you could turn it on. This would allow the player to choose what best suits their needs.
Dynamic/Flex/Whatever you're calling it this week queue - Get rid of it. Ranked solo queue should be just that. A person should be moving up the ladder based on their skill, not the skill of how many higher ranked people they have on their friends list. It skews the system, as your data has shown. In it's place you should add an in-game system for finding ranked 5 teams looking for roles, much like the clan/guild interface literally every other online game with a massive player base has. That way people seeking team play can find a group of players that they would like to play with, if that's the type of league they would like to play.
I've added a couple poll to help prove my point.