> However, we sympathize with the basic problem you’re hinting at, of someone going into ranked with a champion they have never played before, and having your team possibly pay the price.
I think you misunderstood what happens in reality. Like with disabling SoloQ or Draft Pick in EUNE - there are things that look good on paper, in theory but not true in reality.
It is understandable that you fear of new champions (and release skins) not being sold or ranked population getting lower after release of new champions but...
1. It feels like double standards. You ban players for not cooperating with team (SSS case) but you allow players to play champions they definitely don't know which is as much unhealthy. And don't mention PBE experience. We can omit it since PBE population is low and it's not competitively tuned.
2. These champions are banned anyways by those who interested in winning. You basically wasting player's bans for no reason. Look at new/reworked champions ban statistics.
If not a week. Make it a few days so that players would at least get to know what their abilities do and how they feel.
E.g. release on Tuesday. Make them available in ranked on Friday evening (which can also be synced with opening of RGM).