Queue Karma : How to help queue times for non-supports.

I was going to make long intro, but I think the suggestion is actually better off speaking for itself. So here goes.

When you finish a game playing Fill (And thus helping out to alleviate the pressure on role balance), you earn invisible points of Karma. Then, when you queue up at a latter time on something other then Fill, the system removes these points of Karma and in echange increases your chance of getting your main role by a proportional amount. This would also give people a way to help ensure they get a certain role, if they play less desired roles sometimes too.

What do you think?