Would you like to play as a Necromancer with the ability to upgrade Vampires?

20 vamps (if without caches and Castle on the first) will only be available on the 3rd week, when normal players are already breaking Dragon Utopia

For now, you're just guessing, without experience playing them on random maps. I suggest testing with at least 10 single-player games; your point of view will likely not be so one-sided.