Machinist is arguably the biggest let down of a class/job ever to me

[Greedalox]

the heat gauge killed it for me, overheat its HUGE dps lost.

Only if you do it by accident at the wrong time. It's a DPS gain if intentionally overheated during Wildfires 3-5-7-9+ or it's excellent to naturally overheat while AOEing trash packs and then using flamethrower to snapshot the bonus damage on the last second of Overheat which will then carry you all the way past the 10 second removal of GB.

And then there's obviously intentionally overheating before boss invulnerability or phase changes.