Auto-fill in ranked needs to be opt-in / out
As someone who does not mind being auto-filled as I am comfortable in any role, league has always been presented as a game where people can play whatever champion they want. This leads to people who "main" a role or champion, meaning that autofill is not an accurate representation of their capabilities in a ranked capacity when forced outside of their comfort zone. While there is something to be said for ranked being more for players that can be versatile, the mixed messaging that this sends when so many other players "main" a role / champ is made even more confusing by being forced to autofill.
Given that ranked elo change is not (and, realistically, cannot be) affected by players being forced to autofill, this means that in order to actually maintain an accurate representation of MMR changes players need to actually be able to opt-in to (or be able to opt out of) autofilling roles. Without it, players who are not willing / able to autofill and do not queue dodge are putting their entire team at a disadvantage without them knowing it (or being able to change it). Allowing players to opt in / out of autofill (with the assumption that opting out can and will result in longer queue times) brings that closer to an accurate portrayal of MMR.