Well, did have an identity, an actual face, which was added after their codex had been printed. Most of their leaders were sentient, and still capable of rational thought. Look at the descriptions of the Lord leading their kind during the Medusa V campaign. You can call them pretty shallow but a lot of good authors were able to put them to good use, especially Anthony Reynolds and Sandy Mitchell. They managed to make them alien and interesting in very brief appearences, by introducing them in the right way at the right moment like something Lovecraft would create on his darkest days. The current ones though? The last books they were in had a Lord continually saying "I AM DOOOOOOOOOOOOOOM!" and sounding like Robby the Robot with a megaphone. The flayed ones also spoke continuous about needing tailors to replace their "robes" like some bad Monty Python sketch gone wrong, turning horror into bad comedy. ... Sorry, it's a bit of a sore point. Derail ended, moving on. They would serve as a good NPC class, but given their powers and abilities might prove to be somewhat overpowered if the developers stuck to the canon. Plus their Tombs make for perfect raiding dungeons given how many of their kind are usually dormant.