Exactly my point
It is very important from refraining to make serious generalizations, because the three chars have different play styles. I know your strategy is just terrific, but it's applicable with a mage, since you can easily get concentration to a decent level and compensate for the -5 mana per 1-2 turns. The other classes can't do that so easily. I personally get concentration at lvl 6-7, depending on whether I can get that many magic runes available. That's why I like using healing + priests + horsemen to compensate for the lack of mana regen in combat.