I could easily see this getting abused by anyone keeping track of when their attacks will crit.
one, two, three, FOUR. (aims crit shot at enemy ADC)
so like Jhins passive on every other ADC.
The only way people will get rid of crit, is if they replaced it with a damage amp. Which is not too different from how Ashe's kit works now. Except Ashe still has the ability to crit, replacing the extra damage with a stronger slow.
And that's probably one of the reasons for keeping crit in the game, there is numerous utility that can be attached to actually criting, which can be just as exciting and useful as simply doing extra damage. (Ashe's passive, Jhin's movement speed boost, Anyone building ER)