Let's be honest, this really isn't that different from the fucking ridiculous shread of a late game kogmaw.
And Kayles early is fucking abysmal. I'm calling it now, unless her early gets a significant buff, she won't see any pro play. Pick Darius or Renekton into her, and take over the game by level 9. I'm serious, even Kassadin probably has a better early with fleet footwork, his mr passive, and Q shield.
Remember how on current Kayle, if you're level 5 but still decent at kiting, you can Q someone and start whacking away at auto attacks? You even got a movement speed buff if you needed it for your W. That's how I use her as a current Darius counter, you can completely control the pace. New Kayle requires you to be level 16 to start fights with ranged attacks. That completely robs her of her power she has now. You are literally locked into being bad.
Of course they need to make her late game ridiculous. Doing anything else would give her a wr probably even worse than current akali.
Edit: also, how is health not a true damage counter? Something like Chogath or Mundo would probably do pretty well, or at least enough time for Cho to land a Q and everyone pounces.