Hi! Passionate 400k point Yi main. As a heads-up, most of my arguments here are constructed from thought experiments and, when referring to lower ELO, my own experience, along with what I hear and see most commonly when considering Master Yi in a higher ELO.
Anyways, I'll cut to the chase: Master Yi won't ever be balanced for low ELO because of his core gameplay fantasy of a murderous version of "dine and dash," where he avoids hazardous abilities while dishing out lots of damage. If you think about that, this is just a fancy rewording of "I punish people for making mistakes by being really good at the Google Chrome no internet dinosaur game." As a comparison: in fighting games, this is the equivalent of someone new playing against someone who knows what they're doing, where their "unblockable attacks" and "infinite combos" are actually just caused by lack of knowledge about mix-ups, spacing, and punishing. This is also why the majority of players are turned away from fighting games such as Mortal Kombat and Tekken, and why it's summed up to "oh you hit all the abilities in the right order and that's it its' all just memorization." It's the equivalent of a Pyro walking through the center of hightower being Market Gardened and then complaining that they can't possibly do anything against that, like maybe airblast.
This isn't a complicated argument: **Master Yi will never be balanced for low ELO, because a Champion that's designed at its core to punish mistakes will thrive when they're common and suffer when they're not.** Please, stop nerfing Master Yi and either figure out a rework that'll piss off the Yi mains or *let him be*. 9.11 is just a nerf after the "adjustments," which were still intended to be net nerfs, as implied by the words "however, the changes were pretty neutral..."
When 9.10 initially was pushed out, Crit. was pretty much unanimously the real way to play Yi now, which is much more infuriating to play against in lower ELOs, which caused this problem to become worse, since now Yi could two-shot you. Pre-9.10, he was an infuriating mix between a dodge tank and a drain tank, the latter of which was caused solely by the combination of Conqueror, Guinsoo's Rageblade, and Death's Dance. Even the new Alpha Strike change, where it deals additional damage to isolated targets, have increased the disparity between high and low ELO, because low ELO players are more often caught in random areas without teammates where they can be hit by all of the bounces.