Consul spam's important most of the time -- because they are solid thugs, H3 priests, and high command leaders right out the gate -- but if you're not just doing something for the giggles you'd probably want to be doing stuff like taking over water provinces and burying them in reanimators (UW shades are better than land ones, heh, and better or near to it than most of your low H chaff spawn and parts of your national freespawn, too, iirc), and all the normal undead-y junk.
The consuls are easily one of their biggest advantages (probably what I'd call one of the best national summons in the game given they're zero research on top of everything else they can manage, tbh), but ghost ermor still has other things they can leverage. Mostly the cheap/freespawn reanimators that can put out mostly better chaff than skeleton ermor or people ermor (though massing the reanimators is arguably easier with people ermor), but hey, that can go pretty far if you use it right, particularly when ghost ermor has hella' easier access to H3s you don't have much else to do with besides get 'em in fights.
E: Though that does cause the amount of ermors in this game to strike me again. I forget about it occasionally. People ermor, I think splinter people ermor, skeleton ermor, ghost ermor, pretty sure there's a lizard ermor or two, too? Might even be forgetting something. Illwinter likes ermor, apparently.