Kayle has literally zero damage in her kit

Unless you actually play Kayle, I wouldn't expect you to understand this, so I'm explaining it now. Kayle has always had a high win rate, but the reason isn't because Kayle herself is strong. It's because the items she builds are good. Kayle has almost no damage in her kit whatsoever. Her damaging abilities don't scale well, and neither does her 'w'. Until she gets her items, she's not doing much damage. And without her ult it's very difficult for her to win trades. Her ult is literally the only time she's able to make plays. Without those 2 seconds of invincibility, she dies too quickly and isn't able to do anything in fights. I remember before they nerfed her, she actually had decent AP scaling on her 'q' and her 'e', but unfortunately that's not a viable build for her anymore. An attack speed build is pretty much the only thing that works with her now. And she is a LATE GAME champ, so it's extremely easy to shut her down early game when she doesn't have her items.