Autofill. Is. Not. Healthy.
Autofill will,within the game's current state, do more harm than good.
Now, you may say, "Of course not! It's totally productive in the sense it pushes people to broaden their game knowledge and branch out from their comfort zones! Isn't that healthy?" Sure, in an already-healthy environment; when done in a manner that doesn't feel as though it's a form of punishment.
We're here to play an online game, and therein ENJOY ourselves through our CHOICES. Autofill often will forcefully leave players in a role they aren't comfortable with (at the detriment to their team, given .. hey, surprise, this is a team game) or in a role they currently own no champions for, not familiar with the itemization for, or don't possess the runes for. Don't tell me, "Oh please, people seldom get autofilled" when I see on a fairly consistent basis, "Autofilled again already? Really?.." I'm a support main, and the amount of autofilled ADCs I've crossed paths with is outrageous.
It's like, whilst playing a fighting game, having a random, limited assortment of characters to choose from each time you find yourself back at the Versus screen (despite having unlocked everyone). Nobody fucking wants that.
Atop that, this feature extends to ranked play; the land of test-your-mettle. Again, here we are with a potential inherent disadvantage, yet in the more competitive area of the game. How the fuck does that make** ANY** sense? If this was implemented to reduce queue times for higher-elo players, then keep it out of where the majority resides.
or some of the other 5+ supports that are easy to pick up. It wont kill you to play 5 normal games as support to practice.