I think you still get 50% + 50% = 100% dmg boost as opposed to 1.5*1.5 = 225% dmg boost.
I don't think Weather the storm can allow you to exceed the 80% gear cap, but i think elemental shields will allow it. This talent is useful for me because it means I need to focus less on resistances when choosing which gear to use for my character. In my previous game my warrior had 3ooohp, full resistance (80%), and 400-600 dmg output.
At lvl5 Armor Specialist is better than thick skin once your gear armor totals more than 60, but thick skin of 15 armor is an additional 8% damage block out of 53% for an armor rating of 100 and level 19 enemy, say, and about 5% out of 69% for an armor rating of 200 and level 19 enemy. Which I find useful.
proportion blocked = armour rating / (4.5 * (1 + attacker level) + armour rating)
