It might be too much work but in my opinion the ideal upgrade would be job/department specific cartiges that can extend the pAIs functionality.
Some of them could even be locked behind research levels.
There are a lot of possible extensions i can think of ... the real question tough still is if they could be considered worth the required development work.
Rough ideas that come to mind:
Sec cartridge:
Being able to dispense a handcuff every few minutes and being able to recharge stun batons in your pAI.
Medical/paramedic cartirdge:
The pAi can create about 10 units of either saline of epi every minute or two in syringe form, just enough for basic shock/cardiac treatment in case nothing else is at hand.
Or maybe that is it's research dependend upgrade and the basic form has access to the crew monitoring system or even a crew locator.
Mining upgrade:
It could get a basic meson scanner but with an extended view of nearby enemies, to help warn the miner.
Maybe as an upgrade it could even work as a small emergency oxy tank?
Janitor cartridge:
Matter conversion ... meaning it works like a trashbag, but the trash put into it fuels the item creation side of its functionality.
Like for example lightbulbs could be made or even very small not refuelable spray cans with space cleaner (to prevent clown-lube abuse)
Engineering:
Honestly not sure about that one but maybe a diagnostic system ... you use the pAI on a damaged machine or tell it what you want to build and it can give you a readout of the required components or steps needed to fix the machine/door/...
I just see too often engineers that get confused half way trough repairing something and then suddenly disappear to never be seen again
Bureaucratic upgrade:
Allows the pAi to work like a fax or copy machine with maybe as researchable upgrade the ability to function like a telecom console (the ones that allow you to use the radio with tcoms down) Of course with a significant delay inbetween uses to prevent spam.
Illegal cartridge:
Maybe the pAI can even be used for small time crime with an illegal upgrade that lets it work like a multitool, but the electricution form hacking ends up also damaging the pAI severly.
That said, this would be a bit too similar to the door jack ... but maybe someone else can come up with something fun that could be considered usefull but not too impactfull.