It's a really toxic way of soft inting that plagues ranked. If Riot is truly looking for more ways to improve ranked they would not let people "learn" champions in ranked with 0 knowledge of matchups, win conditions, build paths, and mechanics. It's extremely frustrating to have on your team or to have to waste a ban on something every game, when there is something oppressive that you NEED to ban. It's also almost always a loss having someone learning a new champion in ranked on your team. It falsely loses you games you may not have lost otherwise if they player was forced to play a champion they have some knowledge on. It makes no sense to allow that in a competitive ladder.
TLDR: STOP allowing new champions to be played in ranked for the first 2 weeks to a month.