That's the thing about DNC. It's a support job, it's not supposed to be able to match the other dps with its personal dps. They sacrifice their personal dps to give a boost to others. It'll wash out in the end.

Think about it, yeah you may only get 1500 potency, but that 5% spreads to the whole party and will add up, especially if your dps is good. If you have a dnc and nin in the party, you can line up TA with Technical Step for a really strong burst phase. It'll more than make up for any of dnc personal dps.