TLDR; Let people play in their best roles and allow people to keep reduced queue times by making autofill optional. Also

I find I enjoy and perform better in the support role. Being forced to play a game in a role that I'm not going to enjoy, nor perform well in is unfair and a detriment to the other 9 players in the game, especially in ranked where everybody is supposed to be playing at the tip-top of their ability. Speeding up the frequency of games at the cost of the quality is in my estimation a bad idea.
At the very least is it not possible to make auto-fill optional? I understand there are many 'jack-of-all-trades' players out there who are happy to be autofilled for the prize of reduced queue times. I'd rather wait 5, 10 or even 15 minutes for a game of a much higher quality, where everybody is playing in their best role or at least where they want to play, than 2 minutes just to sit on base for the next 15 minutes because some joker is crying about playing support, mid is inting because 'first time Ahri guise' or 3 bot lane because "I main Vayne".
This has probably been explored but I just wish it had more support. I don't really want to play with people who aren't happy in what they're doing for 20 minutes, even if I consistently get my main role. Not everybody can get it and it feels like 9/10 games somebody is autofilled or just toxic.