People shouldn't be allowed to pick a champion they've never played before in ranked.

What if you need to trade champs with another person? That means you'd have to have every single champion played.

Oh sure, I shouldn't be able to first pick for my team mate so we can trade. :^) Oh sure, if my main picks for that role get picked/banned out, I guess I should just go Soraka jungle amirite? :^)

IT EXISTS BECAUSE RITO LOVES TROLLS. WHY ELSE WOULD IT BE ALLOWED?

If they are stupid enough to do so, then there is little that can be done to help them.

This would make it rather difficult for players to trade champions.

what if I get autofilled and the only jungler on free rotation is like who I've never played before

So how an I supposed to get fed off the enemy laner that decides to Azir for the first time in ranked ? I don't support this at all. I love getting fed off idiots.