Honestly, every MRD I can recall seeing in a level 30+ duty has been total crap. Likewise with GLA, or 40+ PLDs that didn't bother questing Shield Oath (soooooo many Stone Vigil runs with Shield Oathless PLDs... sigh)

Even if they can slightly out-DPS a WAR, it's really not worth potentially looking like a gimp for in front of 7 strangers, which is precisely what you're doing when you show up to a post-30 duty as a class instead of a job. When you do it at 50, you honestly just look like you're trolling.

You're better off as WAR so that if it comes down to it you still actually can adequately perform your intended role function.