Splitting the crafts isn't a good idea. I get the intent, but this assumes a good faith that SE would distribute in-demand goods across the branches equally. To use cooking in XI as a comparison, Sushi was a good choice for cooks because the food you could make with the KI was good. Patisserie and the resulting cakes? A joke, really.
As a vague outlook into crafting's future, we know airships have been mentioned. I recall another mode of PvP being in the works, perhaps more cross-server defined, where I suspect things like fortifications, siege weaponry, and other such things could be produced. Though, like housing, these will inevitably need something more than vanity to draw people in, but at the same time, you can't make the activities mandatory as it risks a power vacuum between casuals and hardcores alike. And in the event they do come up with some kind of server vs. server system, being stuck on a world that "sucks" won't do much to help motivation, either.
Now that I think about it, however, crafters can acquire a personal distinction through personal housing and the establishment of "workshops" rooted in the construction of specialized furniture. Making these should obviously be resource intensive, have some kind of resource upkeep cost with use, and later on be upgradeable with more synths added. So, a BSM and ARM would likely want a Forge. Coal, wood, fire crystals, water crystals, and wind crystals stand out as immediate "upkeep" options. Wood is a bit vague, so I could see all being accepted here, but offering different fueling strengths based on type. This is just an example, though, and obviously furniture for all crafts would be needed. You'd also need to lock crafting these specified items to within the range of the furnishing.
"Why not tie it to the FC?!" Well, for starters, not everyone will be in an FC or want to be. As well, the trust of others is always something to be weary about. It's best to avoid situations where one's work is taken advantage of and they're later kicked once they're no longer useful or have a silly disagreement. As well, I feel the economic impact would be greater if it's per individual instead of per group. If it were to be per group, then upkeep would need to be significantly higher. How high, however, would be highly debatable.
"Well, everyone would just have them eventually! So what?!" The upkeep resources are part of the process to both keep the economy oiled up a bit, but also to determine who can and can't produce something despite having the item(s). On a grander scale, I'm not a fan of synths with cooldowns like I've seen some MMOs use, but I could perhaps see permitting only a limited amount per day, otherwise you risk breaking your furnishing irreparably. So, this also means making them should be costly enough that conservative upkeep would be the wiser option with a potential consideration for installation time within your house.
Probably pointless brainstorming from me, though. :/
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