It depends on how you want to play. If you want to DPS, stack Strength and Weapon Skill, then Toughness, then Wounds. If you want to mitigation tank, stack Toughness and Initiative first, and then worry about Wounds, Weapon Skill, and Will Power. If you want to avoidance tank, stack Weapon Skill, Will Power, Initiative, and then worry about Toughness and Wounds. Wounds really are not very important, as long as you are getting healed. No player can burst out enough damage to kill you in a couple of hits bugs excluded. The only way for you to get 2moons dil shorted in this game is though being focus fired. You get hit by 10 doom bolt spells at exactly the same time.
At level 40, Rugged gives you 160 points of extra toughness. The extra armor granted by Ethylic Armor goes a long way in increasing your physical mitigation, and the increased chance to disrupt added to the increased spiritual and corporeal mitigation gained from Bolstering Enchantments means you take a lot less magic damage. This means that you live longer, which in turn increases the amount of damage you are actually able to do.