Almost every mod mod changes Pyre Zombies in some fashion.
Usually it has the Blast ONLY affect the dude they were specifically fighting, and give PZ's extra bonuses to compensate.
But yea, PZs and Life 2 are the last two Vestiges of the old system (Light and Fire) in base FFH. (Fire was one of my favorite versions actually) ... especially the last patch of Fire, magnifique
They work in the current Ice ... but in an expanded system sometimes measures are taken.
For instance ... nerfing PZs and Boosting the Demon Gates.
And having (Nations with no living, demon, or angel units ... aka all their units are undead) to have some extra defense vs Life 2.