Selecting Roles
Before the 2017 season rolled around, there was an experiment where you could, apart from selecting your two preferred roles, also select a role you did not want to play. I can see why this did not work out - I suppose there would simply be too many people selecting to not play support. However, I could see it being different if this "not this role" came back, but only for players who select Fill as primary. This would allow for a way to select four roles, if you do not care much about which role you play, as long as it is not that one role (for me, jungle). I would expect there are far more people that play one or two roles than there are that play four roles, which would mean that the "everyone selects not playing support" would be avoided.
And on top of that Rakan is tons of fun and I think he alone may change the mindset people have towards support.
EDIT: Something I actually forgot to mention, I think that this change may also let more people select fill, as everyone that just doesn't want to play one role can now actually select all but that one, and not all of them will select fill. And of course, autofill could still remain and "overpower" this if there is a real shortage.