HotS-style Matchmaking?
I'm sincerely tired of being the polite guy on the team who calls top or mid, locks a champion, and then has some guy say "me mid" which forces me to support. Don't get me wrong, I love supporting, but sometimes I'm just in the mood for something different... and let's face it. The honor system of call-and-lock is extremely crude and unreliable.
What I suggest is this: A Normals mode in which you choose both role and champion ahead of time, and are then queued appropriately. "But Shingetsu, you idiot!" you'll say. "What happens when some dimwit wants to go ADC Sona?!"
To which I reply, what happens when that dimwit wants to go ADC Sona in blind pick? You either deal with it or you dodge. Not much difference to the way you'd deal with it in this theoretical mode.