The core problem with SOAP was that it inherited too much naive RPC mindset - a simple object access protocol encourages you to think in terms of manipulating o

The core problem with SOAP was that it inherited too much naive RPC mindset - a simple object access protocol encourages you to think in terms of manipulating objects, a bit like COM, DCOM, CORBA encourage you to think of manipulating remote objects via apparently-local proxies. Latency and failure are core to network (and especially internet) RPC though, and something that presents as a method call is too leaky an abstraction. It inhibited people from structuring their network calls as batch operations (the documentation orientation palaver was an attempt to change the conversation) or treating errors in a first class way (errors in RPC are way, way more common than in-process method calls, and require much more attention) or using async calls (don't block the world due to latency, which is rarely a hard requirement locally). All the standardization efforts as the CORBA etc. crowd piled on in and translated IDL (WSDL!), and layered authorization & authentication (rather than use existing HTTP idioms), transactions (WS-AT), etc. etc. just buried the already dying horse.