I don't understand why Kassadin was nerfed and Leblanc is left as is
They both do something very similar. They both jump in and burst you and then jump back out before you have time to react. This combo is repeated until you're dead. You always preach about meaningful counterplay, so please tell me, what is the "meaningful counterplay" to Leblanc? You never catch her because of her safety, and it's impossible to chase her because she'll just stun you. And it's not just leblanc by the way. All assassins have saftey built into their kits, whether it's stealth or some other kind of gap closer. And they all hyperscale. The assassin meta is alive and well. And Kassadin wasn't part of it. Yes he had safety like assassins, but he didn't have the burst that Leblanc, Katarina, Rengar, Talon, etc have.