This seems similar to what is used internally at AppSpotr[1] (disclaimer: I'm a former employee). They also use JSON to represent apps that can be rendered in iOS/Android clients. The difference is that apps must be built using a WYSIWYG editor rather than by editing the JSON directly.

From my experience, a JSON representation works very well for a big percentage of all the apps out there, and you can often do without custom code. Good job creating this open-source version, it looks very expressive and useful!

[1] https://www.appspotr.com/