I don't know if it's hard or not; I just don't know how to do it.
So far, the only unit I've made is the High Seraphine. Typical Caelian stats, No leadership, Stealty-2 Preacher... question, though. Can you even mod the inquisitor ability onto a commander? I don't see it in the modding manual...
I plan on giving the Raptor 'sacred summon' the Howling Bow, or (if I can get it to come out right) a javelin-equivalent.
And, in true dualistic fashion, I plan on giving a new Pretender God that has two forms; in one, very much a classical Virute or some such; in the other, something very close to a Moloch or Prince of Death, but has an attack or some such that generally takes control of undead (or something along those lines).
I _really_ wish there was an attribute called #undeadawe, or fear that _only_ worked against undead. As it is, the Raptors are probably going to be used against non-undead, as opposed to be anti-undead researchers.