I see a lot of issues with Yi's design in this game.
Either Devourer's gotta go, Guinsoo's needs a nerf, or Yi needs a rework. Maybe all three.
Devourer's item synergy gimmick just makes certain items and champions a nightmare to deal with balance-wise. It's either they feast and run through EVERYTHING, or they don't and they're useless. That's not exactly healthy game play. I should be able to feel like I have a chance to stop the bleeding and the snowballing unless I royally screwed up, not feel trapped in a death roll cause the enemy has devourer and a few kills to work with. I should be able to feel like my jungler can swing back into relevance if they play right, not feel like they're hopeless in an investment they won't get any return from. The item is just an item of extremes.
That's where Guinsoo's comes in. Basically any AA-based melee champ can grab this thing and wreak complete havoc. Guinsoo's is its own problem, but Devourer makes that problem significantly worse. This thing just adds a too much 1-dimensional power to rather 1-dimensional champs.
Now with all that said, and onto Yi, Yi is an ASSASSIN. Last I checked, assassins pick a weakened or squishy target, swing in, kill it, and peel out while bypassing as much counter-play as possible. Yi, on the other hand, will ram his "influence" into ANYONE'S ass and usually come out on top if he's sitting on a few items, and it doesn't matter if that ass is a pirate
, a ghost
, Ionian leader
, a ninja
, a bad ninja
, a Demacian bird whisperer
, or a rock
. The only way to deal with this is to postpone it long enough to end the match before he gets the items to auto-win the game almost solo. This sort of design is ridiculous for an assassin champion. This sort of design is pretty ridiculous period. And the worst part is that Xin Zhao plays almost the exact same way, so there's practically two of the guy in the game.
Something's gotta give.