Why not? The more the merrier. A re-skin of existing units with mechanics based on an established template, but tweaked to suit the unit, should be easier than making completely new units. It would add a lot of variety to the kind of encounters you could have and make different groups of undead feel more unique and appropriate to the region they originate from. You’d prevent it from becoming too diverse by only having them pop up when appropriate to the region and their encounters.
Granted, I don’t know what kind of development process they have, so I might be overlooking something that makes this a lot more difficult than it seems.
But good sir orcs are soulless creatures and can’t be reanimated.
That’s just propaganda the clergy feeds you. Everyone knows that the Orc is a proud, misunderstood creature worthy of our respect. Sky has the right idea, we are all equal in death. #Necromancerpride