Different types of heroes in Heroes 2.

As for Scouting, I take it quite often. It's very useful to see what the enemy is planning in advance!;)

No way! It's better to send out a so-called "//shestak//" (that's how my buddies and I call a secondary collector hero :D ) with Scouting. The main hero doesn't necessarily need it!
Besides, once you open the whole map, Scouting will be of no use; meaning Scouting is a temporary skill (i.e., temporary benefit)

And about Ballistics! It's quite important for a hero who stays in the Castle, for example. After all, managing same shooting towers—that's also useful.
Plus, it will be much faster to break down walls during a siege! That's why Ballistics is very important for Barbarians—since they have no flyers!;)