the case of yasuo becoming an assasin
while he is able to deal sustained damage and he has a kit of a rather well functioning melee carry we need to notice that nerfs to his defense forced yasuo to take a very specific aproach of attempting to ult enemy carry and kill him before he gets back on the ground and if he doesnt ... well he cant survive being poked at or engaged on anymore
the thing that i would like to point out that every assassin in our game who was able to burst you down while disabling you got somehow changed
well yasuo is able to pull off such a feat ... and due to reducing his defensive option this is close to being the core of yasuo's late game ... get to ult enemy carry and kill them before they can react