Does the idea of crit chance being replaced with a reliable and equal % damage increase sound bad?

20% crit chance is effectively a 1 out of 5 chance to get a crit. You can get 3 crits in a row with it or no crits for 6 or 7 autos in a row but it is in theory going to normally add an extra autos AD during 5 autos with a chance of being only 5 autos AD worth of damage with no crit or sometimes 7 and rarely 8, 9 or 10.

And yes I know this is Pseudo RNG but I don't know how that calculation works for league so I am just explain RNG. What I do know is that a Trynda with a half filled rage bar when starting a trade has triple critted me before showing how unpredictable of a system this is.

So why does the idea of having it be a % increase on all autos making it highly reliable not sound like a good idea? This would make it always 6 autos worth of damage from 5 autos when at 20%.

And this would not effect IE be it reverted or kept as it is. Current IE would only make the crit damage 10% true and a reverted IE would make the crit replacement 50% more effective.

If the 4% crit mastery back in season 3 or 4 (cant remember which) and the 1% lucky crit rune were toxic why is having trades and fights being decided based on who gets more crits based on a system that is 100% out of players control make any sense.

And this is not like it is any kind of damage reduction. It is just removing an element of the game that does not feel rewarding when it works against you and decides many games based literally on luck.

Trynda is the only champ who would need any kind of rebalancing which he honestly is a way outdated champ anyways, Yasuo would have the new stat 90% more effective and Ashe would have it start at 10% on all autos.

So can anyone actually explain why replacing an RNG system with a reliable one would be a bad idea?