I think much of MCH problems come with quality of life issues the job has. Like the weaving which locks half of all players with not optimal ping out anyways cause well you can't double weave with bad ping. I live really close to my datacentre actually and even i can't play MCH correctly on patchdays or when the game is really congested with players.
Also a QoL issue is the aoe actions MCH has, like that you can't move with flamethrower which makes the action almost unusable in most wall to wall pulls. That the queen has no aoe attacks so basically you can't even use your finisher for your aoe rotation. Wildfire also not aoe tho it could be easily. So many mch actions could be just aoe actions to make MCH actually more fun to play in dungeons without even having to change the job design, like it wouldn't even be a major change. Just kinda unfair that we have jobs like summoner who is basically literally all aoe and then you as a MCH have to stand there awkwardly 10s with your flamethrower which is the pinnacle of boredom.
I would be happy if they bring gunmage back and then make you hit as hard as a blackmage maybe when you go into overheat. That would be fun i bet for most of the players. Better than smothering the job constantly patch after patch cause of some ranged dps tax that shouldn't exist anymore.
The reason why i said that it seems that the devs outright hate MCH is cause the solutions and QoL changes MCH could get seem so obvious and easy to everyone who plays the job for some days. Yet SE only response to people begging time and time again for changes are again and again buffs to wildfire and other potency buffs. Which is almost never enough to even compete with other jobs let alone casters. I don't get why they are so scared of seeing a ranged dps for one patch cycle on top, so scared that they have to literally drag MCH everytime to the bottom of the list most times even below the supports. So either they don't know what to do with the job or well they outright despise it by now.
But the worst part is the silence about it, while they talk about buffing other jobs who often do fine. MCH players have to scream and beg while getting kicked from groups for playing the job and then get some small breadcrumbs in form of another wildfire potency buff.