Cat's Grace will only help your dwarf's attack bonus for:
a) ranged combat
b) using small blades and has the Weapon Finesse feat
Without the Weapon Finesse feat, all melee attack bonuses are based on STR. Bull's Strength or Champion's Strength is much more valuable for your axe-wielding dwarf.
In fact, there's not much value in having a dwarven fighter or barbarian with an 18 DEX. You're better off maxing out his STR and CON. You'll more bang for your powergaming buck that way.