Shyv, Yi, Xin, Kayle, Warwick, and sometimes Kindred and a few others. From this change, the only ones being hurt by it are Xin and Yi.
Shyv and WW can now Jungle till 6, take drag on their own time (level 3 dragons, anyone?), and gank post-6 whenever they have ult. They don't have to worry about stacking anymore, which is great for them.
Kayle and Kindred didn't ever get devourer for the on-hit double-proc, it got nerfed to the shitter for them. They got it for the attack speed. They LOOOOOVE this, especially Kindred who is focused on early ganks, which this item allows for. (more so than Devourer, at least)
Yi needed this nerf, but he'll still love the physical damage. The nerf to this means you only have to build 2 stats against him instead of 3, now. HP and Armor, he won't do enough magic damage anymore to matter. (Guinsoos being super expensive, Bloodrazor doing Physical dmg)
Xin will suffer for I estimate about 2 patches from this. They'll buff him, he'll be op for 1-2 patches, then he'll be fine in both lane and jungle. So 3-4 patches from 6.9 (so around 6.12) Xin will FINALLY be viable in lane again and not just jungle. Overall a huge plus for Xin.
So basically, overall, Yi is the only one who got truly hurt by it, which makes me SO happy because I'm sick of seeing him...