@Riot I'm glad you are looking into Nocturne but this "buff" is not the way to go
So I just look at PBE changes and Nocturne is getting an AP ratio added to his passive. Nocturne Buffs...YAAAY...not really.
This is such a weird buff, rageblade was never really good on Nocturne and neither was the sated devourer. I'm still messing around with bloodrazor and I think its definitely an improvement over devourer (I am actually starting to prefer it over Warrior) for Nocturne but trying to get rageblade to be part of his build is pointless, he has no on-hit effects on his kit like all the ex-devourer champions and pretty much prefers having armour penetration in his builds (which you since made it harder to obtain since you made yommus more expensive and removed the armour pen from warrior). Blade of the Ruined King use to be core on him but most people just go warrior -> yommus since blade got nerfed.
It's starting to sound like a rant right now, but tbh I dunno what Nocturne exactly needs right now. It's not even like he's bad but other champions right now do his job a lot better. Only significant trait Nocturne has is that ult. It's good you want to give Noc some love but I don't think this is the way to go.
(In case anyone is wondering what I've been running with bloodrazor, Core: Bloodrazor -> Blade of the Ruined King -> Yommus/Trinity. Runes And Masteries: I suggest Armour penetration reds, Attack Speed Quints and Fervor of Battle or else you're gonna be losing a lot of damage)