Honestly, one of my bigger frustrations of using Habitats is just how unreliable the special deposit system is due to the requirement that special deposits be based on the planet, not the moons, a Habitat is built over.
Specialized habitats are great when you can get them, no joke. Special resource deposits getting multiplied make for great refinery habitats. Science habitats are exceptionally efficient. Even just being able to build more worker districts is a nice expansion to your economic base if you're role-playing a non-expansionist build.
But these resources have to be over the planet to be accessed, not asteroids and moons. That's frustrting, as there's been many a time I finally unlock habitats and the resources to spare and look to build one and... there just isn't a good place. At which point it's still good- habitats let you take industry off your planets and specialize gravity worlds for raw resources- but not as good as would be easy to justify.
While by no means a fix, I do wish habitats could get deposits not just from the planet, but a planet's moons, and that you could build them over starts (the source of most science deposits).
Habitats could rather easily be improved to be far more interesting, and for moons of planets to contribute rather than being ignored as they are at the moment.
I always play with "Guilli's Planet Modifiers and Features", at least after it's been updated to the newest version. The way habitats work in that mod is that it adds a set of decisions to unlock extra stuff on habitats, some generic ones conditional on things like system trade value but most of the powerful special things are unlocked by either modifiers on the planet it is orbiting OR modifiers on any moon around that planet.
Here's a fun habitat:
Ignore the other stuff in the picture, I was roleplaying a relaxed isolationist game relying on defences and never invading but getting attacked from both sides from the very start... and I was actually a fair bit behind the AIs with a slow-growing lithoid that avoided building any CGs at all (we all make our own fun). Anyway...
The habitat is getting the option enact decisions costing alloys and unity to unlock special planet features. These features add 1 extra max district, which is great, and a couple of jobs, which are also great but can be a bit OP (but balanced around those jobs also being given for free on special planets anyway, the precursor jobs give minor relics for example, but the minor relic costs are all higher to compensate).
The habitat is getting bonuses not just from the gas giant alone but from things like the Hiveworld Fossils anomaly effect on the moon of the gas giant as well, though it's still limited to only getting one type of special district (the hive world on the moon has unlocked the decision which has unlocked research districts on this habitat for example).
It means that building a habitat around a gas giant with a dozen moons is almost as powerful as it would be in reality, or in good fiction (like the Expanse series). The only downside is there's no expansion planner for habitats (or branch offices) so if you build a lot of habitats you do have to manually check systems for good locations or perhaps leave a construction ship as a bookmark for where to build later. I'm always a bit annoyed if I see crystals on the map only to zoom in to find they are in an asteroid field (the mod doesn't change that annoying feature).
I'd love a developer to play with the mod and be inspired to make some fun updates to habitats for the vanilla game. I do worry that with planets getting significantly better that habitats will be relatively weaker in future. Ideally you'd update things at the same time to avoid leaving anything behind... it'd be odd to upgrade lasers for example before kinetics. So I do find it a bit strange that planets will get lots of very cool new toys but there's been no mention of habitats yet (other than to say that you can't have both around a planet). Fingers crossed they haven't forgotten about habitats.