MCH biggest issue?

[Idolon]

As I recall, Cooldown (above 50 heat) is equal to a Heated Slug Shot, so it's hardly a loss to "never use", plus in those rare occasions where you don't want to push for or need to withhold an Overheat but you're already near 90/95, that's when it still does its job as intended.

I wasn't saying it was a damage loss to never use. I was saying it's a boring, underutilized skill now because it almost never needs to be used. I also didn't say that it was useless, but that in the ideal scenario, the only reason you use it is because it happens to be better than split shot and there's no downside to using it while overheating.