I'll say it again. Stabilizers is a must or merc dps. And it's not for just 1v1. Unload and powershot are a huge part of both dps mechanics you need as much protection on them as possible.
I used to think it was a must. The thing is, when a melee is all over you...Stabilizers is going to get you killed. You can't trade Power Shots with any melee class out there.
And against any other ranged class, you are going to lose the fight anyways if all you have available is Power Shots. Even an uninterruptable Power Shot vs a Sniper or PT will get you killed if you swap blows. The only way to beat enemies is if you have your main rotation available. (and thus, no need for power shot)
My only use for Power Shot is when no one is attacking me. I'm very happy to free cast. But I don't trade blows unless my main rotation is ready. Or in the rare case I need to finish someone off and everything else is on cooldown.