My suggestion for crit chance

When I think of Critical hits, I think of it as my character "finally hitting the chink in the armor"

It works alot like black cleaver. Anyone with crit chance on your team applies a stack of "crit" on an enemy auto'd. When an enemy reaches 100 stacks the last person to auto attack the champion deals 200% damage. If the last person to proc the crit off of an enemy has IE the crit does 250% damage. Crit stacks dont remove until champ goes back to base. For example, Caitlyn(35% crit) and jax(10% crit) target enemy amumu. 1st auto comes from caitlyn-amumu 35 stacks 2nd auto comes from jax-amumu 45 stacks 3rd auto comes from caitlyn-amumu 80 stacks 4th auto comes from caitlyn-amumu 15 stacks and takes 200% damage from the last caitlyn auto

I think this suggestion covers critical chances identity and the damage its supposed to apply. It encourages focusing on specific targets and helps out poke based comps that were dominant primarily on the random crits they'd get poking under tower. It feels alot less like a yi or caitlyn passive and more like a battle that benefits the team that wears out the enemies armor first. I was trying to stray away from yi, cait, vayne, and braum passives. Give me thoughts though and ask questions on anything you dont understand.