On the note of making Machnist the APM job, it should probably be through a passive like Greased Lightning for a 20% cast time reduction while Hypercharge gives another 25% cast time reduction. This would bring MCH to a 2.0 base second apm while keeping the 1.5 second Hypercharge window except that skillspeed affects your Hypercharge windows .
On a side note, stuff like Hypercharge and Lemure Shroud could probably be both converted into 40% cast time reduction as they are now. In fact I don't know why they keep devaluing skillspeed/spellhaste by setting certain abilities to specific cast times, I would love to play faster versions of jobs other than BLM.
As for melee chainsaw in that other post... this is what I mean by Machinist's rotation being inflexible. Unlike SMN who rearrange where their melee phase is, Machinist's optimal rotation is set in stone from the start of a fight. A melee phase would feel novel until the point that boss mechanics force you to drift from your rotation and you forever hate it from there on out. It could be fixed with charges on all tool weaponskills like Air Anchor/Drill, but then we run into the problem where there's almost no skill expression with MCH, hence why it needs a rework for a different form of skill expression. Yeah, the only way for MCH to get a melee chainsaw phase and not hate it is a rework and it's actually one of the reasons I strongly feel like MCH needs one.