An idea to delay the burst of crit champs and to reduce RNG (discussion appreciated)
How about a 'crit gauge' that fills up every auto attack/ability that crits. Once filled up, every auto attack will always critically strike without fail. But before it is filled up, you deal normal auto attack damage. When you go out of combat, your crit gauge resets.
Building crit items increase how much the crit gauge increases per auto. Let's say, if a crit gauge is fills up at 100, having just a zeal (with 20% crit) will take 5 auto attacks in combat before you start critting.
eg. In an extended fight, a 100AD adc with 20% crit, will deal 100 damage (before armour modification) for the first 5 autos, but then gets a power spike and start dealing 200 (250 with ie)%.
It will also allow more counterplay for champs like tryndamere. With max rage, you can fight him for 3 autos knowing how much damage he will do, but then you should stop fighting as his autos after that will always crit.
Thoughts?
Edit: to avoid confusion, 100% crit will mean your crit gauge will activate immediately (like current ashe passive) so the late game adc will still be there. It will just give adcs a choice between early damage or building for the late game.
Edit 2: A reply I sent to a commenter:
I agree that the balance and decision making would change A LOT. But it might be healthier in the long run. here's my thinking:
It would mean adcs won't be as much of a priority target, allowing decision making to not be solely around the adc. Focus other enemies, and you don't have to worry about burst as much. But if you ignore them, they will hurt in the extended team fight as they should. Assassins don't have to focus the adc. There's mages, supports (seriously. Kill the soraka or janna if you can) as targets for assassins.
Secondly, it will give windows of power in the bot lane so that a losing bot lane will be able to come back, without the aid of ganks. EG. the enemy adc is 3-0 (and you're 0-2) is just coming back to lane with higher stats, but you were at your wave stacking up your gauge. Then you engage at that moment since you have the crits while they didn't, giving you that window of power to beat your counterpart.
Finally, kiting will be that much more important. Unlike just running away, weaving autos (orb-walking) will allow you to get that crit spike. It will seperate good from bad adcs even more.