[InsainArcaneBirdbrain]

I'd say that Katana Master being compatible with any sub weapon in Destiny is fair GRANTED if Kensei is your main class. It'd give a good reason to choose Kensei as your MC in the Destiny lineup instead of being sub fodder, and would hold it back from just being a free Kensei mark applier/abuser alongside the strong MC skills of Ghost/FB such as Wraithguard and Plume Echo.