Voss isn't leadership material, simple as that. Any others are relative nobodies and/or are too loyal to Sylvanas and what she represented.
You see a destruction of "Forsaken identity", I see a much needed deviation from an entire race depicted as saturday morning cartoon villains based on a mix of Tim Burton aesthetics and evil alchemist-wizard Rasputin in Anastasia. The entire Lordaeron part of their identity has been in the background for far too long, and "death to the living" was a road leading absolutely nowhere when considering long-running story arcs.