As someone who never really played MCH (or ranged physical at all) until Shadowbringers, I'm not as burnt out on the job as a lot of others seem to be. But after 7+ years of caster play, I can see where folks are coming from.

For me, the changes I would like to see are simply better interactions for abilities. I don't really want to see new abilities, as I feel the number of actions is just about perfect as is.

For example, I would like to see the ability to use Air Anchor and/or our combos to extend the Queen duration instead of just building for the next one. In the end, I don't think it will change uptime for the queen, but it would give us more depth in how long we can maintain Queen uptime around certain phases of an encounter. I wouldn't mind the ability to refund some battery if you recall the Queen early (say to avoid immune phases or transitions).

I would love to see some interaction between Bioblaster and Flame Thrower. Maybe Flamethrower doing increased damage on targets that already have Bioblaster. I would also like to see Flamethrower build heat. The idea would be that Bioblaster+flamethrower is our main AoE, with Auto Crossbow and Split shot being filler in between.

Reassemble should do more than just give 100% crit chance. Reassemble+Drill should allow Drill to hit all enemies in a straight line, giving it an AOE component. Same with Reassemble+Air Anchor should create a circular AoE as well. Single-target it won't make much difference but may have some usage in boss fights with add phases where Bioblaster isn't necessary, or if there are maybe 2-3 targets to cleave.

My final idea would be to have Auto-Crossbow act more like Hypercharge and reduce the CD on Ricochet/Gauss Round.