In my opinion, WS-* lost not because of the format or verbosity. WS-* lost because the concept is about the continuation of RPC, where you expose custom methods that can be invoked from a client. When state is altered in custom ways, complexity goes through the roof - to the point where you need a DSL (WSDL) to define these methods and how to interact with them.

REST simplified things because the concept is about limiting the method invocation to the bare minimum and always have an explicit understanding of the state that is being changed or communicated.

The XML/JSON question is not as important as the method/resource question.