I don't think it is fair to orient developers towards JAX-WS. JAX-WS is
a dead API, and the industry has moved beyond SOAP. JAX-WS stopped
evolving in 2001, and I don't think it stopped because it was
feature-complete.
A standardized proxy framework would be welcome because all JAX-RS
runtimes already provide one.
https://java.net/jira/browse/JAX_RS_SPEC-496
You must admit that there are very little REST API's leveraging the
HATEOAS principle and that JAX-RS offers very little to promote the use
of HATEOAS. Poor man's tools like Link and URIBuilder are simply too
limited to achieve the RESTafarian dream of fully decoupled
applications.
What I see in practice is lots of boilerplate JAX-RS client code with
hardcoded assumptions about the API.
Additionally, there are ways to define a proxy API that is more
powerful and that makes abstraction of a strict URI scheme. e.g. by
providing an alternative for the constant @Path annotations and taking
a Link argument (coming from a previous interaction) instead.