Thing is, there's no real reason to have a different stonesense config per save. If a save doesn't have something, it just won't show up.
Of somebody mods in pet dragons with custom scale shearing workshops, and makes stonesense graphics for them, they just have to be added to the same stonesense config as everything else, and they'll be use for any scale shearing workshops it finds.
the only thing you would have to do to merge a separate pack with the rest would be to add a folder to the central index. Doesn't need to have the same folder structure of stock stuff.
Yeah, I don't really foresee a player having radically different graphics in different saves, so it's kinda overkill as a feature. This is entirely to make the mod-manager folks comfortable with handling visualizer data. They're fine with arbitrarily complicated file structures within
raw/, but anything outside of that folder risks them becoming responsible to maintain N different custom merge logics, and I understand their hesitation there.
The functionality I'm envisioning is a spot inside the
raw/ folder that Stonesense scans for indexes without requiring all mods to be in the same
index.txt file, and understanding relative paths from (1) that spot and (2) the generic content store. That lets the mod manager import the content, and it allows two independent mods to co-exist without any complicated text merging. To comport with player expectations, per-save stuff should have precedence over generic stuff.
I'm not sure who is going to want
Awakened Stones and
Daleks in the same game, but it shouldn't fall to the player to merge indexes by hand.
The most complicated use-case could be putting beards on female dwarves. That requires taking precedence over the generic DWARF creature, but ideally referencing the assets that already exist in the standard location.
Any per-save awareness wouldn't push out widely until a new version of DFHack is published (probably with the next version of DF itself), so there's every reason to think this through and make sure it's a mechanic that's lightweight for the devs and works well for Armok Vision etc. that will consume similar data.