^ sorry, EUW here.
As for the new Yi, he looked broken on paper and is broken. Here's the issue, it's not because his Q can crit, it's not because he can reset that, it's not because he does true damage blahblah. All of that is great, sure. Here's something interesting in case anyone was wondering why Yi is so strong right now.
Here's the problem: You can't itemize vs current Yi. When he activates highlander he's immune to all slows. Now you usually 100% want to buy a frozen heart/ randuins to counter a.speed champs right?
Randuins usually being the one that's most preferred because it can be built on no-mana champs and is slightly more cost effective to build. So you buy a wardens mail, and now every time yi hits you, he gets his a.speed reduced. This is great.
Now you'd think you'd want Randuins (the upgrade) ... well, no you don't against Yi, because the a.speed slow DOESN'T WORK against him due to his highlander.
Unique Passive – Cold Steel: When hit by basic attacks, reduces the attacker's attack speed by 15% and movement speed by 10% for 1 seconds.
That's Randuins passive. It now also reduces movementspeed, but it applies both of these together, NOT separately. So buying a randuins is actually doing nothing to prevent Master yi's super a.speed crit damage resets because in Highlander, he ignores all slows(and thus, a.speed slows). It just gives you the stats it shows and the active ... which is also useless vs yi.
It's one big noobtrap. You're
forced to buy a frozen heart (literally the only item in the game to stop a highlander yi's a.speed unless you want to stick with a wardens mail all game) to stop yi atm and most junglers aren't optimally built for one as are most top laners.
So what else is useless against yi because it applies a slow AND a.speed reduction at same time? Nasus's wither, Nunu's iceball/ult, Lee's Cripple, Anivia's ult, Darius cripple strike...
The ONLY 2 champions in the game that can reduce Master Yi's attack speed, are Malphite and Gragas (barrel roll) because they're just A.speed slows, not a.speed + movement speed slows.
So, before the next patch nerfs come (he's being nerfed!) start abusing him now lol.