I've taken a long break from Yi due to the tank meta and his reliance on farming so much to hit a good spike so it's not very impressive right now, but anecdotally it's feeling a lot stronger than just building attack speed in runes and items until midgame. My winrate with Yi in the past 3 months has fallen from 62-56% and my KDA dropped from 2.8 to 1.8. This drop has been using Devourer>BotRK based builds. I played about 15 games preseason with the hybrid on hit build and while undoubtedly strong, it relies on expensive items to add up together into a functional machine. This build gets large spikes from individual items that synergize with one another, but aren't reliant on one another to be functional.

I don't have enough games with this build to say that it would be supported data. Picking Yi needs to be done with consideration because most teams expect the jungler to bring some cc or initiation. If you end up with a Zed mid and a Vlad top then Yi would be terrible over someone like Wukong or Amumu, so I don't pick him a lot. I have mained him since season one with over 100 games in ranked every season(rip AP Yi). To me Yi has been at his strongest(not counting the true AP builds pre-rework) when 3-5 enemies aren't tanks, itemization allows him to efficiently stack penetration to slay squishies, and when the enemy tanks rely on slows such as Nasus, Mundo, and Tahm. Interestingly enough, I discovered that you can get your Q animation off while Tahm is eating you. You take and receive damage in this situation and then are consumed.

One of the big things that I like with Warrior is that it improves your sustain in the jungle much earlier than regular builds with Devourer. The preseason change that gave jungle items LS vs monsters makes getting 2 good AD items early very good for sustain. Imo, being higher HP and using less mana to clear makes me more able to countergank, survive counterjungling, and to duel at crabs.

The reason that Devourer is so touted is because it is absolutely the way to get the highest possible dps on Yi. That is non-negotiable, it is so. This path gives you cleaner clears through better sustain, more frequent ults through cdr, and higher burst damage in 2-4 AAs.

2-4 AAs is really what I'm focusing on with Thunderlord's and Shiv. Yi only brings damage to a gank. The amount of time that a gank exists as a 3v2 or 2v1 is often very small. People roam, junglers come, flash happens, cc is real. With one item, Warrior with Challenging, Yi is able to deliver 2-3 AAs and a Q. Thunderlord's at level 6 with 60+13(E) bonus AD does 82 damage. Your AAs themselves will deal another 145+11.5 true. Your pen at this level will be 20 flat Arm pen and 8 flat M pen. Q will do 240 dmg. Q+2xAA+Decree will total to 82 magic, 23 true, and 530 physical damage before mitigation. Common mage pages use HP/lvl seals. Most squishies will have less than 40 armor even if they have seals. Lux, Heimer, Veigar, Thresh, etc. will only have armor left after your pen if they took runes or built items at this point in the game. This gives you very close to 640 damage in about 2 seconds. I haven't even included challenging smite's damage in this which is also true damage. With 2 AAs, say you get 4 seconds of uptime on smite's DoT at level 6 you will do another 120 true dmg.

I'll try to spam Yi for a while and get some data up. I think this will be the way that Yi mains go while the Cunning tree is having its heyday. Using QSS>Scim as my standard LS item also mitigates return dmg from Thornmail. If having to deal with 2-3 users of that item, which is pretty common, I would go for DD or LDR as my last damage item instead of a second crit item. I would still want either Shiv or PD for AS anyway. I like Shiv for the burst as it's adding yet another source of immediate effect. DD and PD combo seems very interesting to me though. I think I will choose that route when I'm vs other strong duelists like Tryn or Udyr.