Rather than bake SOAP support directly into the core Atom protocol, define a separate SOAP Gateway mechanism in a separate I-D. Doing so will decrease the complexity of the core spec and will provide a good separation of concerns
The core specification should focus on the minimum core functionality necessary for enabling Atom. Introducing SOAP into the core require us to deal with two different models for implementing the protocol. A cleaner layering using an Atom-SOAP Gateway defined in a separate I-D would make more sense.
Defer the definition of a SOAP binding for Atom to a separate I-D.
Client -> Atom Protocol
Client -> SOAP Gateway -> Atom Protocol
Remove all normative references to SOAP in the core protocol spec.
Model the SOAP binding as a "SOAP Gateway for Atom"
Simplifies the core specification.
Isolates the SOAP binding to it's own I-D