30% damage reduction is the problem, it's far too high. It's a major advantage unfit for a barbarian, barbarians are power hulks, not soldiers, they would rather lower their own defense in order to gain more offensive power. Although this isn't a rule, it would be easier to rename the class to a Warrior instead. Monk also got 30% damage reduction, which I also find an unfair advantage, Wizard in this case should receive 30% damage boost, Hunter as well. Just to follow the logic.
By logic, a Monk would be a very balanced class, attack and defense on a monk should be nearly equal.
Hunter would not forsake defense, but would instead input stealth and attack abilities to use as it's defense measures. Evasion would be a Hunters defense in most cases.
A Wizard would mainly have a few defensive spells, but seeing as magic and physical damage is practically the same now (just pointing out that armor will protect from both) it would just need some bubble, and forward everything else to lay waste on enemies.
A barbarian is a typically offensive class, like I said, it's not a rule that all Barbarians are kamikaze, but 30% damage reduction is fairly high.
I think there shouldn't be ANY defense reduction buffs since armor works on all damage.