Necropolis in the third game is a very interesting and original faction. It is in no way inferior to, and in many ways surpasses, other factions. The concept of the undead is very, very appealing. I personally perceive the undead not as walking corpses, but as another side of existence, on par with life. And the heroes of Necropolis are simply great!
And Necropolis is indeed a very balanced faction that is very different from its other neighbors.