My wishlist for 6.0 is simple, it may be slightly too early for that but they might be in the process of imagining what they'll do with the job next:
-Rework Flamethrower, don't make it a trait, rework it, it's a shame to see this cooldown defining most Machinist in such a state.
-Better heat gauge, no one like spamming one ability and Machinist spams the most of it. It's bad, no one likes it and it's not friendly towards latency.
-Wildfire, rework it or delete it, either goes in the trashcan or rework, it's a bad 120s cooldown with no interactivity and no thought process beyong Hypercharge.
-Don't make another Choice GCD there is too much of it on MCH, you'd better not make Noise Blaster useless with a shared cooldown on Air Anchor. Also don't even dare about creating a choice between AoE and Single Target Automaton.
-Interactivity with the Automaton Queen, I know MCH have been asking for Lead Shot or a dot since its removal in HW, but giving a cool looking Automaton to MCH then making it a glorified dot is as fun as making turtle races between each other for a salad.
-Test the job and its rotation, how comes there is no one in Square Enix trying Machinist job and not pointing out how Wildfire has no interactivity, how there is a heat problem with Barrel Stabilizer and how you can't fix it for a simple QoL?
-Show us the "Love" for machines, there is many times where Yoshi-P claims the teams loves Machines but Machinist had to wait a whole Stormblood expansion to fix a broken job and barely any changes happened on Machinist during ShB? Shôha was reworked when it didn't needed to be and could work this way for a whole expansion without bothering anyone.
-Rework the ranged rôle, in HW, ranged were the top of the support DPS. In SB, ranged were the top of the support DPS. Support was the keyword but the rangeds are now in a mess of a spot where they don't have damages, no support and all they can do is bring a 1% bonus stat to the team. MCH is limited to Tactician when it had Refresh, Palisade and Dismantle.

Please Square Enix, it was a good beginning but give us the other half of the rework.
It's tiring to see that the Machinist only shined in only half of an expansion. It was bad in SB and brought nothing in ShB and is a bore to play. The only reason you want to bring a MCH over the other ranged is because it's the best thing in the trash can. It's not the rotten meat named Bard, it's the half eaten apple.

And that’s it.
Sorry about the pâté, but 3k characters is way too low to have a correct debate.