Existing Wording: Operations can also be executed asynchronously. In this case, the requester sends a message requesting that an operation be executed, and the destination system subsequently sends a message back with the results of the operation.

Given the increased complexity of the asynchronous use case, the implementation has increased complexity. As a summary, asynchronous operations are performed like this:

Proposed Wording: Operations can also be executed asynchronously. In this case, the requester sends a message requesting that an operation be executed, along with an additional parameter in the querystring to define a callback URL. If the Operation request is accepted, the server returns a 202 in the response. When the Operation completes, the server will POST the response content to the specified URL

Comment:

Using messaging for asynchronous operations is overly complex. We propose a callback-based scheme similar to x-callback-url which is a well-established means for asynchronous operations over HTTP.