What change do you want to see on your main class for Endwalker ?

[Soge01]

More Explosions for Black Mage and more turret techs for Machinst.

[CKNovel]

BLM could get Comet, a lesser Meteor. It would be a nice symbolism with space travel and XIV starting with a meteor and BLM ending the story Arc with comet.

More Explosions for Black Mage and more turret techs for Machinst.

Turret tech when the expansion actually removed the turret? Or more interactions with the Queen? I agree to the second but I'd be carefull with the first.
Bishop or "Automaton King" coming back could be a Queen 2.0 or AoE version and that would be disappointing.
A stronger version would mean the "Automaton King"/Bishop is still a glorified DoT.
An AoE version would mean you'd never see the new bot in... 90% of upcoming 8 man content and sometimes in 24 man raid.

Also, "Solo actions" in open world/solo duty... We already have the chocobo in open world, a far enough healing buddy. Lost Actions in Eureka&Bozja. And The Echo buff in solo duty.
The best solution would be to buff the chocobo, maybe with new actions, and that's done. Why bother balancing solo action? Is the goal to do old EX/Savage content solo when many have mechanics that needs to be dealt with multiple player? Then you want actions to deal with these mechanics aswell?

[ItMe]

Bishop or "Automaton King" coming back could be a Queen 2.0 or AoE version and that would be disappointing.

My pipedream is that we get the Automaton King (or whatever) and it's big enough we pilot it ♡♡

[CKNovel]

My pipedream is that we get the Automaton King (or whatever) and it's big enough we pilot it ♡♡

I'm not a massive fan of Mecha and it would be a massive downer for me. ^^'
I'll be honest and admit that I, on a personnal view, hope it will never happen. I love MCH for the use of tools and guns (and bigger guns), I love robots as well but piloting one? I think it should stay exclusive to G-Warrior content.

A "pipedream", next to a chainsaw and reworked Flamethrower would be to summon Ark, there's already Cruise Chaser for the animations/skeleton.
Ark would act as a Satellite, the MCH giving order for Satellite attacks, mainly AoE. Completing the requirements could allow the MCH to summon Ark on the battlefield like the Queen.
But one-step at the time, for now my expectations are very low when it comes to MCH. In the last LL, Yoshi-P had the ranged jobs in his action bar, maybe he is playtesting the jobs. But that's speculation, maybe he's simply an active ranged player.