Match maker discourages unique play styles.

Essentially, it ended up sucking because everyone chose to veto Support, which lowered matchmaking quality and increased queue times dramatically.

Autofill was introduced as a last resort way of ensuring people don’t sit in queue for a ridiculously long time.

Riot is saying ranked queues must contain top, middle, bottom, support, and jungle. It's hard coded.

Autofill discourages such teams as top, middle, support, support, bottom.

I think it's too early to declare roles. Definitely too early to be declaring champions. I think a champion select must contain "role distribution", "bans", and "champion distribution".