The pet is weak, that is both for the Mystic and Defiler.
As for DPS you can turn your spells into combat arts(melee) for the Mystic for more damage. Personally I did not like the long pauses inbetween while I was waiting for the attacks to refresh, I find going down the INT line for a Defiler can bring you some ok dps and the fights a little more interesting. (Just my play style).