[Arthas is frustrated. Dark rangers are so variable...]

Intangible undead have limited sense. Embodied undead have no way to escape if they're attacked and can't heal themselves like the living do - when we get cut, the cut stays open. She's a ghost inhabiting a corpse. She's bound to it, so at the moment she has the downsides of both.

I know that having power would let her escape her body if she needed to, and to vanish into shadows to hide. They'd let her heal herself, at least a little.