Thing is, its not that unique, its just a bigger customisable Ushabti, at tougher opponent that unless you pay out for the extra arms is not going to do that much damage, and not that much fun either.
The reason why I like the Ancient Warrior is that he is a constuct yes, but one I can imagine in Nagash's Legion, a superior more skilled version rather than just copying the TK. Pus he's fun, a mincer when working but worrying about keeping the controller alive, as your opponent hunts him around the board knowing thats the weakness.