What would be the best strategy in perfecting the warrior?

With the Barbarian I would suggest that you put all of your level up stats into strength and using jewelry that increases strength. Two hands are a must because they have a higher amount of damage. The only 6 skills necessary to max out in his skill tree are Slashing (Blunt weapons is optional, but the best weapon in the game is a Slashing weapon), Bind Wound (really only necessary if you want to help save yourself in a quick pinch), Slam, Critical Hit, and Call of the Ancestors. By using both Critical Hit and Call of the Ancestors, and then hitting an enemy with Slam with a dagger that does about 200 (at level 50) can produce a critical hit that does around 20k-25k. You can spend whatever skill points that are left over to any other skills you feel necessary.