Machinst can kill even with minimal battle high using Drill/LB combo, provided its against a non Melee job. MCH is not to be underestimated even if it isn't a meta role.

As far as the turret goes, which my mindest also applies to Sage due to its LB, I see more value in denying my enemy team damage, then putting out an AoE with minimal DPS that people will just walk around and ignore. The debuff it puts out on enemies even though it increases their damage taken, it really doesn't have any value and you don't need it to effectively nuke people. The other fun thing you can do with Machinist is coordinate with another Machinist, and instantly wipe out people from full health with 2x Marksmans Spite. That especially applies to Astrologians with BH V in DRK premades. Because if you can't stop them from mowing your team down, you can at least disrupt their gameplay and make them a bit salty in the process.