Absolute skills

These are just some of the most striking and versatile examples. In real-life situations, things are even more complicated. Let's take Kaspar, for example. He's an excellent starting hero for Necropolis. We managed to get Logistics (a truly remarkable skill, and his abilities in it are excellent). And what's next? Necromantic spells can probably be skipped, but defense is a very useful thing. And... that's it! There's no room left to invest in Spell Power. Only one type of magic (two is rarely useful anyway; the losses are small, especially compared to the majesty of Logistics) and Education. What would you prefer? Logistics with Pathfinding and the potential for Warrior skills, more useful abilities in Darkness/Summoning and Education compared to those needed for Spell Power, defense, which, unlike Spell Power, will provide a STABLE reduction in damage, not to mention Resistance and Hit Points, or Spell Power itself?
For specific heroes like Naadira, who already has two magic skills at the start, Spell Power can be tried, but this is more of an exception than a rule.