If you want to win, pray to RNJesus!

Ah, crit. Their is a reason why it is wise to always have more than zero. You can either never do double damage, or sometimes do double damage. The difference is a 1% crit rune.

To rely on chance for your damage, and to be balanced around that chance for damage. Yikes. This means whoever builds crit is essentially Schrodinger's Cat. You won't know if you will never crit in a teamfight, and potentially fail. Or, always crit, and potentially win. Starting the fight is like opening the box.

I don't like uncertainty. Especially in a test of skill.
RNG has no place in a skill based game.

A better model for "crit," is fiora's passive. Critical damage is centered around the idea of attacks on a living organism hitting critical areas. In order to simulate this, RNG was used. It is just tradition at this point for games to have crits. Crits don't take skill to land. Landing headshots, and hitting vital spots, does.