Excluding both factions professions, I'd say either a mesmer or necromancer would be best, because a monk doesnt have enough energy for an ele, and a /war or /ranger seems...wrong since you are a healer not a damage dealer.
Since you CAN change secondaries AGAIN, feel free to just try out a mesmer or necro secondary and if you dont like it too much, or dont find it too usefull, change.
mesmer or necro if u want energy recharge elites, ele if u want the defend skills and warrior if u just wanna be in the back of the party and away from the warriors who atk u