I personally don't mind autofilling, but what it does to players who are strictly role oriented completely ruins the game.
I think if the queue goes above a certain amount of time looking for someone to fill the support role, then just start the game 4v4 with no supports. I already play a bunch of 4v5s due to someone having to autofilling support on my team, feeding the first kill or two cause they dont play the role, then leave the game.
Right now we're already being flexible with picking 2 roles. Give em 3, heck even 4. But to stick someone in a role they're not competitive with and have their competitive ranking be affected by it is nuts. Imagine if you were in the olympics for track and field, and they stuck you in some swimming matches, and have that affect your final score ranking for track and field. If one role is severely under represented, that's a Riot problem, not a player problem.
Alternatively make the dodge time longer. If that person is that disgusted with the role they'll sit out the timer. I'd rather have them out of my game than in them anyway.
ANOTHER option would be to pop an autofill queue notification. If people are willing to do it they'll fill, if not they wait longer. If you're giving people the option to autofill and they don't take it, then they can't complain to Riot about long queue times since they're willing to wait.