Okay, let's talk about skills. Here's what I think should be absolutely essential.
First, Earth magic. That's a must-have.
Tactics! Water magic. Because both the Moon faction and the Necropolis have spells and units that need to be countered with the "Expert Forgetfulness" skill.
For the Necropolis (in my opinion), resistance is needed. It turns out that resistance doesn't appear for Elementals (what a fool I was!).
The last skill for the Moon faction was Magic, so I decided to keep it.
Is there any progress on your complex map? I'm interested in the continuation. Or have you abandoned it?
I remember that the map seemed like a challenge to me. I'm wondering how long people will have the patience to play it. :)