Honestly, it is the reason for so many issues in league right now. By it's nature, all crit champs end up building pretty much exactly the same way since it's multiplicative damage makes building non-crit items super inefficient. This in turn makes lots of crit adcs play super similarly, due to both being auto-reliant and their power spikes basically being predetermined by the items they are buying. It basically forces those adcs into not having agency for most of the game, since if they did, their inherently powerful late game wouldn't have reasonable counterplay.
I've seen some people suggesting turning crit into a flat % damage increase, but that really only gets rid of the rng aspect, while leaving the rest of crit's issues.
So why not just get rid of it? Just make more unique attack damage items. Split essence reaver into the Mana passive and the cooldown refund passive, like it should have been. If you want crit-like elements in a champion's kit, just put it in their kits and make it unique to them. Thoughts?