auto fill is a horrible idea
so just now i played a game where your support was obviously auto filled into the role and he didnt want to do it at all so in fact he didnt, he took smite farmed the jungle, which in turn got our actual jungler as well as him grossly under leveled, hung our adc out to dry while there jungler invaded out jungle as he wished and got fed off of our 2 under leveled junglers. i would much rather have long wait times then have someone stuck into a role they dont want to play and then troll the game away to a loss because of it.