Generalize.

1. You can have 1 BP/1 BO called GET resource which gets:

  • resource id
  • resource type

And based on that information constructs the required JSON.

2. If BP only proxies requests to BO you can skip BP and call BO straight from BS.

Check out RESTForms2 - it does something similar (CRUD over classes) and there's only 4 handlers for all classes.