Maybe set up a checklist of roles you'd like to play when you select Fill?
I see a lot of people complaining that they want to play 3 or 4 roles, but don't want to select fill because of the 1 or 2 roles that they're afraid of playing.
Maybe Rito could put in a sort of "toggle all the roles you want" option for Fill.
As a support main, I don't really want it for my own roles, but it might help ensure that my teammates aren't forced into roles they're uncomfortable with.