MCH Overheat should activate automatically

[Shurrikhan]

The GCD that triggers overheat could also be a different one that then transforms into Heatblast.

I don't see why we'd want to spend a button just for that, though? If it had a big bursty hit to start things off and we could later reuse it for a less efficient but burstier use of stacks, sure, but otherwise we may as well leave it on the same key.

Plus, the animation is kinda weird, you make your lunchbox sparks then it makes your gun shot faster?

Agreed. Stormblood Overheat never had enough visual or auditory feedback prior to actually hitting max to make it feel like it was heating up the gun, either, but at least it made some sort of sense.