Just loaded up a custom with the skin, and uh, first day buy. Holy hell. It's beautiful. I'll edit when I play a full game with him on any further particle/whatever inconsistencies but damn Riot... good job with this skin.
Couple things I noted were that the passive stacks seemed excessively noticeable, and would definitely look obnoxious on an enemy champion with one of the golem buffs or Baron, or worse, all three (or even Runaans orb thing...). I like the brightness, but maybe smaller size? The ult animation is amazeballs, and while I surely do love the small projectile on his Q (actual arrow size not giant dog red rocket colored arrow), I feel like people will be confused that the hitbox is reflected in the particle trail of the arrow as opposed to the arrow itself. Lots of "omg that didn't hit me wtf nerf". The voice is obviously out of place, but that's been mentioned. That's what I've gathered in the time it took me to hit 6. <3 this skin.