Not a single champ sits at over 92% so far, showcasing a better, more balanced game. However, there are a few champs with an incredibly high presence that have an abysmal win rate, Syndra and Renekton. Read about them here:
It's no secret that Pantheon is a problem. He has been banned in all but one single Play-In Stage game, and was, of course, immediately first picked and won the game. But this has been problematic before, and it needs to be fixed.