Critical, surge and power are useless?
If you're wearing champion gear you have lower stats and an expertise bonus. Expertise does nothing for PVE content. However, it should still be plenty for hard mode Black Talon from what I've seen.
As has been mentioned. You are probably not the problem. Your DPS is severely lacking if the bosses are enraging at the 10% hp mark (it's a time limit, not an hp limit).