If only Blind Pick is left, you might as well bring team builder back.

Team builder was superior to both normal draft and blind pick in every way.

No fights over role. No getting a role you didn't want. No getting your champ banned. No getting sent back to the queue the moment 1 person screwed up. The only thing anyone was able to say was bad about team builder was the queue times, which they also said about every other queue and was A. exaggerated and B. exacerbated by people still playing blind pick for some reason.

TLDR: Team builder was the best system you had, go back to it.