Contrary to other stats, strength grant benefit only each second spend point, duplicate disappointing feature of DD3ed mechanic. Also the warbook skills didnt take Str into formula.
solution: let strength grant additional HP, when not boosting damage. f.ex. strength give even levels: +3 HP & +1 dmg
odd levels: +5 HP.
Strength would be more viable among other stats, if the HP grow come mostly from it. Player then will take into consideration increasing Str for his mage character, due to increasing his survivability.
Suggest HP grow; INT+1, DEX +2, STR +3/+5, OCC +2, PER +1.