Another group that would be impacted disproportionately are a lot of the ones that are prime transferable-skills ones. In an economy like Yamatai's, a lot choice civilian trades might assume on someone had a specific job in the Star Army. Check out my Merchant Spacy for Yugumo, you can see what roles assume a certain SAoY background, and they aren't all mainstream ones that are either bridge crew or away team focused.
So we should look at the solutions that don't involve axing too much stuff, and see if it maybe something on the chopping block should go into an alternative solution box rather than being slashed, before we slash it.
Is it a case of maybe there are jobs you have to have to submit a plan for how they would fit in, or can't be your first character, or you have to have done X first, or a GM or something needs to invite you to play, or "This is usually an NPC so if you want to be one you have to make a really really good case why" or something?
Are there occupations or specializations you get into mid-career? Like Diplomatic Attaché in the US Army. You can't just enlist as one, but they recruit NCOs mid-service for it. Special Forces used to be that way until the US needed too many of them for the ol GWoT and they started taking candidates off the street.
Are there any that should be sub-specializations? Are there any that should be skill identifiers?
So maybe there are classes of them? We tier it up like how was suggested for RP requirement levels.
Very Easy Tier, anyone can pick these in any "typical Yamatai plot":
Anything that is obviously bridge crew or away team focused, like the bridge stations or any of the infantry (Yamatai uses these where Starfleet would use security), command, or field science types
Easy Tier, a little more specialized:
The stuff that is onscreen a lot but not as much as above, like the people in Medbay or Engineering
Hard Tier, Most of these have in common that they are very specialized so they're harder to use outside of a plot focused on them, but they're perfect for plots that center on them in which case they're the bridge crews and away teams of that story and it's all good:
Fire Support combat units like fighter pilots and tankers, special operations, military police, intel operatives, random lower decks type technical staff like technicians outside engineering, supply, and cooks
Very Hard Tier, most of these are really out there and rely on players to make their own fun
Anything not mentioned, but Cyan got into it above
Special Tier, these things tend to be things the SM/FM/GM/Admiral Player wants someone to handle
Basically just Admin clerks and the Co-GM playing the XO