I'm actually very close to your defensive stats, which makes it obvious that I'm just not that good at this build. I did switch to force armor for Belial but I didn't think to switch back to it for an entire act. Do you use force armor for Diablo himself, too? I've failed in my 4-5 attempts at him using prismatic.
I wonder if I should try force armor for A3 farming. I've gotten so addicted to 1k resists that it will be hard to switch back to the old ways!