I really wish "fill" wasn't just another word for "support."
I always fill, and I don't mind supporting. But when I pick fill, what I really want is "random" so I can just play everything, but have the game decide for me. Keep the game interesting and fresh.
But right now if you pick fill, you get support like 85% of the time.
Wish they'd fix that. Or implement another position called "random" that actually just randomizes your preferred position.