i'd rate undead rogue above mystic and possibly WH, and sage possibly above merchant (and that's a very big possibly)... but i'm going off on a tangent.

in general though, undead/rogue isn't viable, and the kingdoms that could make it effective at all have far better options. i guess it's okay if you have to follow some silly dictate to run all undeads, but why on earth would you want that?