I think the Barbarian should have the following skills:
1. Logistics - Pathfinding - Path of War - Death Strike.
2. Luck - Magic Resistance - Barbarian Luck - here, 3 skills aren't that important, choose based on your preference.
3. Attack - Battle Fury - Tactics - Ranged Attack
4. Defense - Endurance - Evasion - Magic Resistance
5. Choose either War Cry and all skills with faces, or Leadership up to the speed aura.
I've played many times with this build, and it doesn't matter if it's a mage or a warrior against you, this Barbarian will defeat everyone easily.