How I Think Crit Should Work

I'm just gonna say it. Crit as a % chance on every auto attack, like it has been for the past 8 years, has been completely impossible to balance. In any given patch, marksmen are either completely broken or completely worthless, and it all revolves around when they can get their triple crit spikes. But, what alternative is there?

Well, what about incredibly reducing crit % numbers across the board and making it % max health physical damage instead? Or, every X basic attacks (based on your crit), you will do bonus % max health physical damage? This would require reworking pretty much crit items as a whole, but it would fix several problems with ADCs:

1: Burst. If an ADC can get their triple crit too early, they can outburst most other champions in the game when they're supposed to be the consistent damage champions.

2: Tank Busting. ADCs are supposed to kill tanks, but not so much squishier characters. Limiting most of their damage to being a % of the target's max health allows them to continue doing high consistent damage to tanks, but deal less damage to everyone else, and making the % max health damage be physical means that there is still counterplay to it.

I don't know how good an idea this actually is. The idea just popped into my head and I haven't put any more thought into it beyond this, so I'm interested to hear your thoughts.