An Opinion On Kha'Zix
Well since there's a lot of threads on the bug lately, I think now would be a fun time to jump in.
So I've commented on this before, and hopefully this will give you guys a good idea of where I'm trying to go with this.
What if Kha'Zix's evolutions are designed around his Isolation mechanic? Doesn't it seem odd to anybody that despite his duality in unique mechanics, having Isolation and Evolution, they have such little interaction? Kha'Zix's Evolution mechanic for example plays a role in interacting with his Unseen Predator passive thanks to invisibility triggering it, and evolution increasing the amount of times one can go invisible; that's a good case of synergy within his kit.
Isolation however has very little application with his Evolution mechanic. One of his Evolutions straight up relies on it to be at its most effective but there's no way to really trigger it as Kha'Zix lacks the tools to really do anything other than hope his target is far away from others. Even that is difficult given how big Summoner's Rift is, and how few tools Kha'Zix has to travel long distances.
I don't play Kha'Zix very heavily and so I won't pretend I know what he needs, but I certainly do think it would be good for his kit if it had much more synergy. Maybe if his E evolution was linked to traveling longer distances, like an outside of battle movement speed bonus, for example, which solves one of the problems I mentioned earlier. I honestly think if Kha'Zix had more tools to pull more reliability out of Isolation mechanic, it can go a long way to making him a far more consistent champion, and put him in line for necessary buffs and safer nerfs.