Secondary skills in Heroes 3.

My preferred skills for large and complex maps:
1. Wisdom.
2. Logistics.
3. Pathfinding (especially where there is a swamp).
4. Earth magic.
5. Air magic.
6. Fire magic.
7. Water magic.
8. Diplomacy.
I don't play on small maps, but I think there you should develop skills that provide additional damage instead of points 4-7 (ballista, attack, archer, etc.).