Bork not working on a dude known for deleting squishies in 3 crits is not surprising. And if it worked before on Yi, it's probably a good thing it doesn't now.
The reason for the nerf to the bork passive is to balance out everything ELSE added over the past couple of months that basically puts bork on steroids.
- The sated passive
- Runaan's being good on every other adc now
- Kog with attack speed that blots out the sun
- On-hit hybrid champs getting a little more love
Bork was fine until these changes, but was due for a nerf the MOMENT Riot changed devourer's. But if Riot nerfed it then, it would have hit too many non-jungle champs reliant on bork at a time when none of them had additional steroids that balanced it out. Choosing to nerf it in the adc/sustain patch was excellent timing. After that patch, EVERY bork toter had the synergies to compensate for a bork nerf, instead of just a few champs. Most people shunning bork now don't seem to get this. It's actually as excellent a dps item as it was a few months ago.
Maybe not for EVERY scenario. But if the mixture of nerfed stats with boosted synergies has now turned bork into a niche tank-busting item, well then... GOOD! That's what it was SUPPOSE TO BE FOR ALL ALONG! The whole point of these changes is to add some serious tradeoffs between different champ/item choices, rather than have a bunch of ubiquitously effective picks and builds that are spammed to the point of monotony. Bork was one of those items. Ever seen a zed rush a bork against every squishy mage in the game? I have... on every Zed I've ever seen. What's wrong with this picture?
Riot is trying to address a long-standing problem that, in trying to add one item/champ/mechanic for one specific purpose, they tend to make things that are either a) not really useful for that or any other purpose or b) useful for that as well as all OTHER purposes. This was never a good thing. Riot's finally finding a route to reaching some of their longstanding game-mechanic goals. Balancing these items in isolation to recorrect their course has never really worked. Riot's new approach of COMBINING changes over MULTIPLE items/champs/mechanics to tackle specific problems of specific items is actually working rather neatly (still hate that SR games now end at half builds though.)