A mechanic for critical strikes

So recently Jeremy (the guy on the video) made a video about the critical strikes and discussed wether its RNG nature was a positive or a negative thing in the game. One of the points he addressed was that the critical strike presence was dictated by pure luck and it didn´t really have to do with anything regarding skill from either of the players. I would like to propose a mechanic that, in my opinion, would be very interesting to see in league of legends.

Imagine that there was a mark on every champion´s body that represented its weak point, the closer someone clicked on another champion´s weak point the more dmg its auto attack would deal. This would give the player some sort of control on the dmg output of his critical strikes. Items wouldn´t even need to be changed, they could make it so that the critical strike status would increase the radius of the dot up until a certain range. Also, for people that use the A click to auto attack, their critical strike percentage could be just normal like it is right now.

I know this would be a really hard mechanic, first to code, and then to use by players, but for me making the game harder equals making it more interesting. I would like to know your opinions on the veracity of this mechanic and whether or not it could be fun to use. Also the points and challenges that i didn´t quite addressed.