exept machinist is not supposed to be a pet jobs, the turret is like a dot, that why machinist have only one dot.
Dot+Rook Tower = 100 potency, it's like one auto attack bonus, but other jobs do have 70-80 potency dot combined and deal far more damage.

that where the trouble lie, the dps of the machinist is far too low in comparaison of the other jobs.

i will not talk of the gauss barrel mode that are simply garbage, the loose of the auto-attack is way too much in comparaison of the +20% damage.