PT's have higher dps in Pyro. Snipers, it depends on the fight. Sorc is viable in both specs, although lightning is theoretically better.
They do have higher dps in Pyro, but AP has some nice advantages on certain fights thanks to faster run speed, interrupts (helps in HM EC), more AOE (trando phase in HM EC Kephess) and 30% AOE reduction (always nice for your healers since there's always unavoidable AOE damage in these fights).
The drawbacks to AP is less single target DPS (but still more than enough to easily carry their weight), less burst DPS, and a priority rotation that requires a bit more thought than Pyro's (but still isn't very complicated).
Anyways to answer the OP's question, the only DPS classes I have not run a HM TFB or HM EC with to date are Operative/Scoundrel and Assassin/Shadow. That being said, I've heard Lethality works out OK for Operatives and Madness for Assassins, so just stay away from Concealment/Scrapper and Deception/Infiltration.