While the core capabilities (items, item groups, and recipes) are in, I suspect I will be adding things to this for a good while, as I have a lot of ideas and not much free time to dedicate to it, and Cataclysm itself is of course changing a lot right now on the JSON front. But that sounds like a great idea. In a week or so when more people have (hopefully) tried it out, we might be able to consider this a “stable build”. You could start with that. I can probably finish a major feature every week or so, and I at least want to do Professions, Monstergroups, maybe Vehicle Parts, some more advanced searching capabilities, and a Mono port, for now.
EDIT: Tilesets, also, when the JSON for that settles down.