Necropolis or Castle (Which one is stronger?)

I think it's Necropolis. When I played as Castle, I almost always lost!

Well, it just means you're not playing well!

Actually, I think you're doing it wrong now, when you take the map and the player into account. For comparison, you should take:
1. A symmetrical map
2. The same number of hiding places and other objects.
3. The same number of resources and units.
4. Part of the Necromancer's map should be covered in dirt, and the Humans' in soil.