If you're are used to tank classes but want to DPS play a Powertech / Vanguard, Jugg / Guardian or Sin / Shadow. Jugg / Guardian is probably the best of the three for DPS right now but Powertech / Vanguard and Sins / shadows are getting a pretty big buff in 2.8. Shadows / Sin can stealth past things though.
Even in DPS spec you have taunts and such you can use with the exception of the jugg / guardian, the AoE taunt turns into a threat drop in DPS specs. So you might feel a little more familiar with things.