Strength
Increases physical damage and critical hit
Vitality
Increase HP, HP recovery rate, resistance for critical hit and max weight
Intelligence
Increase magical damage and block penetration
Spirit
Increase SP and SP recovery rate
Agility
Increase hit rate, critical hit rate and evasion
Basically all the physical damage class(Swordman Archer) will go Strength and Agility for damage and critical damage.Magic damage class(Wizard Cleric)will go Intelligence and Spirit for magic damage, max SP and SP recovery.
Then Vitality is only for some swordman class go half tank or full tank. My opinion is they should add some physical defence and magical defence into Vitality as well, Otherwise if physical defence and magical defence can only increase by equipment and skills. Then the advantage of full tank Swordman to the others will be some HP and HP recovery only, and no damage. What do you guys think about it? I think they should buff Vitality stats. 

I don’t really have a solution to any of those problems either 