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It's interesting, to be honest, to hear about preferences for secondary skills.
I would like those who prefer skills similar to those described by Roman2211 to share their gaming experience; I completely agree with Marmot and Alexeagle on this.
My opinion, which is, however, purely personal, is this: I am absolutely sure that combat magic is generally useless in real battles. The maximum power of the "Explosion" spell that I have ever had was over 10,000 units (with a sphere). In truly tough battles, this is just a light tap!
I advise everyone who disagrees with this to find a "difficult" map, for example, "Armageddon." Where you need to "defeat" 8,000 Azure Dragons, I'd like to see who can do it with magic and what army they will need to survive at least a few turns. And what about magic if you are fighting those who are immune to it? Try fighting an enemy with "Power of the Dragon Father," and you will understand me; and if they have "Armageddon," then that's a real treat! This also applies to dragons and golems. The "Sphere of Vulnerability" is not available everywhere.
Here are my preferences for secondary skills for the ideal hero: attack, defense, archery, earth magic, logistics, pathfinding, air magic, wisdom.
Moreover, earth magic is the most useful of all magics ("slowing and speeding spells can be a powerful weapon, especially in the hands of EXPERIENCED warriors"), because it is much harder to live without a city portal and regeneration, and "Dimension Door" and "Fly" allow you to travel long distances, and whoever can travel further has an advantage, which is why heroes with good logistics are good.