Replicator hardware is pretty cool, but man it would be so cool to work on the software. How to best represent huge assemblies of atoms so the file size is small and easy to store/quick to transmit. How to pick the best file format during a scan. Foods probably benefit from a different compression algorithm than engine parts; we don’t want proteins misfolding because the atom placements got averaged out into a “flawless” lattice.

How to adjust that format when someone wants to edit a pattern. People usually aren’t looking to pluck individual atoms from one pile to another, and depending on the object polygons might not be the easiest primitives either (someone editing a garment wouldn’t want to nudge a bunch of tiny triangles to adjust thread tension). CAD primitives work in some cases but they’re mostly designed around subtractive manufacturing. Even 3D printing tools are optimized for fewer materials and layer-by-layer construction.

How to facilitate someone “zooming in” to mess with the crystal structure of a material, then going back to working on large macro-scale shapes. How many in-between levels of fidelity to simulate and store between those zoom levels. How to handle materials that have a smooth gradient from one material to another, so there’s no sharp dividing line where we can assume there’s a bunch of identical molecules.

How many background calculations to run. In addition to the basic physics, do we predict failure points? Replicator energy consumption? Can someone zip bomb a replicator by replicating something that seems simple but actually consumes an ever-increasing amount of power?

Do we scan for compatibility with other items already in the replicator library? Speaking of which, how do we organize the library for efficient search? Are there Federation citizens whose full-time calling is to be tag wranglers for replicator patterns?

Peak Star Trek is when some rubber-forehead aliens are cavorting around going “teehee look at how humanoid we are! we have the same problems as you! this is a Metaphor” and then the camera pans to a Federation human who is regrowing their own limbs like a salamander.

Since holograms come from interference patterns, it’s tricky to make good holograms with shorter-wavelength light. The shorter the wavelengths get, the tinier and tinier the details need to be in order to align the wave peaks and troughs correctly.

If any of the Star Trek aliens are UV-sensitive, they probably don’t get all the hype around holodecks. Every time they try to play, everything looks all blurry and off-color.

Conversely, any aliens that see mostly in infrared might have picked up holodeck technology earlier, or used it in more things, because holograms look extremely crisp to them. Maybe they assume it’s just a basic optical illusion, having stumbled onto the effect way before they knew how electromagnetic waves work. They’ve got complex 3D holograms appearing in kid’s books where other species might have made popups or Magic Eye pages, because they can make infrared holograms with relatively coarse-grained printing techniques.

I assume once the Star Trek blinky-light medicine gets halfway decent, there’s a fad of “““ergonomic””” chairs that are silly impractical nightmare shapes but with a tricorder and a bunch of tissue regenerators strapped into the cushions. All the post-scarcity artists and crafters are pretzeling over their projects for 104 hours straight, then standing up refreshed and comfortable, because they had the automatic Carpal Tunnel Eraser switched on.

Junk

Ferengi whose hobby is making slick, glossy, totally impractical replicator patterns. Like these things look cool and photograph great but they break in the middle of their first use.

Since she’s stuck at home bored, she makes so many of these damn things. She takes requests, and since they don’t actually have to work, she can fill weird niches no one else has made patterns for. They dominate every list of replicator codes, even though everyone who uses them gets SO annoyed immediately. Many assume they’re “using them wrong” and re-replicate them to try again, so they seem really popular even though they suck. All of them have a discussion thread a mile long, which perversely just increases their profile even more. Of course, she can’t read… but modern computers have text-to-speech, so she gleefully follows every complaint.

I haven’t seen every corner of Star Trek, but I assume there must be an episode where some cosmic silly is Annoying the captain and suddenly they go “I too have a Star Fleet” and we look out the viewscreen to see a docile herd of stars bobbing past.