AoE combo being Spead -> ACB -> FT is not bad.
It would make use of Flamethrower for once. I wish for flamethrower to be a bigger part of MCH tool but that idea works.

Turrets, not fond of the idea. SB MCH was actually this:
Summoned turret -> Hypercharge -> Turret overdrive -> Replace turret when it's back.

It wasn't excessively fun and on top of Ammos, the job was more around micromanagement.
If it was added, I wish it would disable the turret rather than replace it. MCH playerbase hated having to replace the turret.
But SQEX couldn't fix the turret and at least disable it rather than replace it everytime. That is, within a 2 year window.
And it would make the turret a "place and forget" pet. Not really fond of turrets, outside of Hypercharge, they're just more auto-attacks.
It's either bland, either micromanagement.

Wildfire... There is more to fix than the lag.
The two main problems about Wildfire is that it doesn't do much damage over 10 minutes and Wildfire gameplay is "Press the button, resume rotation", it has no interactions, you press Wildfire, continue to play and 10 seconds later, damages.
You could make it a 120s cooldown with 1200 potency it would remain the same. In my opinion, Wildfire need to go, this cooldown had its time but it only works with previous MCH iterations.
About the lag, there was a good suggestion about making Wildfire a 5 stack debuff, each GCD would reduce that stack by 1 and reaching 0 would trigger the damages. The core functionnality doesn't change but it's more lag friendly.

Reload was not hated, it was more the RNG aspect of Machinist that was hated.
But in the current iteration where combo is 100%, Drill and Air Anchor are weaponskills? Wouldn't work.
What you can do instead would be giving side effects to the 3 GCDs and being able to use them in the order you want.
One GCD could inflict a 60s DoT, another could deal strong AoE damage and the last would increase battery. That's of course an exemple.

The problem with reload is that MCH tends to go further and further towards the use of Machines rather than guns. The more it happens, the more Gunner is more likely to appear. It truly depends on SQEX wishes.
Many problems comes from the fact that MCH was intended to be a gunner with gadget, but they failed and created that weird and ugly Chimera.

And that's a problem I have with your suggestions. There is some ideas but it's a throwback to HW/SB MCH rather than making the job evolve.