Camouflage is pretty underrated, at least in dungeons. Even with the parry nerf to 15%, a 50% chance of parrying should average about 7.5% physical mitigation. So GNB has 17.5% physical mitigation and 10% magical mitigation for 20s on a 90s cooldown, compared to Thrill being ~16-17% of both for 10s (90s cooldown) and DM being just 20% magical mitigation for 10s (60s cooldown). It's not the best skill for tankbuster mitigation, but the other cooldowns cover that anyway.