suggestion for "fill" roll in new team champ select

Hey, I don't have a PBE account, but i try to keep up to date on the changes going up and coming to league. Having read a lot about the new champion select, i thought i'd throw out my 2 cents.

I like the fact that there is a 'fill' roll, and think it's very useful, I often simply 'fill' in most blind pick games, however I know I'm a very sub par ADC though i can play the other rolls at a competent level. What if you could lock in "fill except X" where X could be your weakest roll. you're still volunteering for 4 of the 5 positions, this just helps you keep out of one position you hate/can't play very well.

I realize this would probably most often be used with people saying "i'll play anything except support" but I don't think it's a bad thing if someone says "i can do anything except one roll pretty good"

thoughts?