Posts from Secondary skills in Heroes 3.

I try to make sure that the main hero has: logistics, earth magic, attack, defense, leadership, and/or luck (these two skills are almost equivalent), tactics – these are the 6 main ones, archery (if there are 2 archer units in the army), if the map is large, wisdom + air magic, and preferably intelligence, pathfinding (if there are many sands, swamps, or snow on the map), navigation (if there is a lot of water), fire magic (if you manage to quickly create a berserker). Eagle Eye, First Aid, Artillery, Ballistics, Literacy, Training, Scouting, water magic, resistance, estates, mysticism – forget about it. For In the Wake of Gods, the setup will be slightly different, but I haven't played it much.

Here, we're only talking about the main hero. For secondary heroes, I take skills related to estates, literacy, and artillery. Water spells, when earth and air magic are available, are usually left unused, so I don't take them. As for resistance... there are more important skills, and there's no room for it. It makes sense to take it if there's a chance to acquire artifacts that grant magic resistance.
Tactics is certainly a debatable skill. Sometimes it helps a lot, and sometimes it's useless in every battle on the map.
What makes ballistics particularly good for Barbarians? To charge into a town with behemoths?

Come on, you can play as a Wizard and use Earthquake to destroy walls.

yes, but the magic turn will be spent on this earthquake instead of casting debuffs on the enemy or using spells on your own units!

Yeah, that's true... well, what can I say... take more flying units and archers!

In my opinion, it's easier to take Ballistics!:D