More Support
Clearly, the least desirable position to play is support. Hence the reason that "Fill" and "Support" have a 50% quicker load time. In addition, if one chooses "Fill", s/he will almost assuredly be supporting.
I think that LoL should reward the unselfish players that play support in the traditional way. Maybe some sort of increase in Riot Points, treasure chest drop rate increase, or some other reward might balance out the people willing to play a support role.
Just a thought.