I know his entire kit is outdated, and if he was released today he would've been almost completely different, but I feel like putting a Mana cost on his W is so cruel these days.
He's primarily played in the jungle, where his W isn't even used except for the dragon (and it's not like Nocturne can spam the spell at early levels), and this might actually help him out a bit to fulfill his role.
His Q+W+E is like 60% of his Mana, add his ult cost and you don't get much left, thus fulfilling the "either you're too fed to care or you just ult on someone and die" prophecy of early LoL assassins.
P.S
As someone who plays tons of ARAM these days, let me tell you that's where it hurts the most.
