If would be nice to be able to set REST API "Send Default Options" per API Method request vs a fixed value for the entire REST API parent endpoint.  Ideally each API Method should be able to set the REST API "Send Default Options" option on a per request basis based upon a referenced or calculated valued based from Site, Header, Input parameter, or Method Output parameter.  Depending on the consumer of REST API, there tooling might not be able to handle complex JSON structures with missing parameters.  This idea would allow optimization of JSON responses for clients that can handle sparse data while at the same allow non advanced clients to be to use the same REST API.