I mained Kayle in season 7 and 8, accumulating over a million points on her. I just played the new Kayle for the first time vs humans and I have to say she is beyond horrible.
Her visual update is excellent, no complaints there but her new kit is pure shit. She is a completely different champion and far weaker than the old Kayle. To be honest, I'd rather her old kit but with the new visuals. She is quite easily the weakest champion in the game. In fact, she is the weakest champion I have ever seen in all my time playing. She is completely ineffective for most of the game and when she does become something resembling a normal champion, the match is already over. This new Kayle has to sit out the most important parts of the game. In terms of just her kit and numbers, this is by far the worst rework I have ever seen.
I always planned on maining her again since she was always my best champion but now, I almost 100% sure I'm going to drop her. Riot really fucked this one up. And if I can't get as much success on another champ as I did on her, I might just quit the game. It's really no fun not having a champ you know you can pull out when you really want some wins. Kayle was my champion of choice for just winning games.