Some People don't know that warrior tanks in DPS staces able to stay in position let them push out higher numbers then a DPS running out of random AOE.
There have been times my wife the FC only Warrior Main Job, has push numbers hire then DPS because of 3 reasons. One Able to take a hit without moving out of POS so more DMG being done in the fight, Not dieing, Just being out geared over other DPS in the FC. She can play WHM/BRD/WAR. but only War is max Ilevel. Our FC lets people for the most part play the job they like not the one they are best geared at.

There are 2 people in our FC that have been posting our fights to FFLOGS. which I personally don't care for I play for fun.. If I can't beat content today. next patch I can try again,

If you play BRD all the time and you finally get DRG geared to enter content knowning the rest of group is going to pull there weight. Sure play DRG because maybe your sick of always playing BRD.
In this case the DRG DPS is going to lack that of the BRD, but the person gets to have fun.