Why are crits still a thing...

I was SO happy when I heard they were reworking adcs at the start of preseason 6, it seemed like the only problem with them at all was crits, so that would be the obvious thing to fix. Apparently they don't give a fuck that crits can determine an entire lane which can easily determine an entire game based of off RNG. If anything they just made it worse now that essence reaver gives essentially random mana regen. This would be a problem in any game, but one that you can literally win A MILLION DOLLARS based off of the outcome? That's completely insane that this still exists in the game. It's not even remotely hard to fix either! There are a very small amount of champions that would need to be changed because their kits revolve around crit, but other than that, just make crit increase your auto attack damage by the percentage of crit you have. It's the exact same amount of damage in theory, but fights won't be won because someone got luckier. Crit isn't a huge problem against tanks because it tends to even out more based on just the sheer number of hit they can take before going down, the huge problem is when adcs 1v1 each other. Two or three lucky crits in a row can and almost certainly will determine a fight. I don't know what else to say, it blows my mind that riot can consider their game competitive when crits still exist.