It's not that he's portraying how RZA wants, it's that he isn't conveying RZA. The actors studied with their counterparts, or watched tons of footage. It's everything in the dude's delivery and presence that throws it off. When RZA talks, he commands attention, even though he talks with a quiet demeanor. There's no way you watched any RZA footage, or listened to RZA and came up with what this guy is bringing on screen. That's on the actor. You have personalities like Rae, Ghost, Uey, Dirty - all loonies, and strong authoritative dudes like Divine & Power in the Clan hierarchy, and they listen to RZA. None of the people on the show, as played would give this actor as RZA, control of their lives for 5 years.
Ghost dude doesn't sound like Ghost, doesn't look like Ghost, is charismatic but doesn't have Ghost's charisma, but he's killin it. East has Meth's quirks, and Shameik Moore went to a Rae school to get everything down..same for dude playing Divine.