Agreed, When i started SOAP around 2000, it was very simple. After that we for more into the awful WSDL 1 (WSDL 2 is better). But the number of WS-* and the different implementations that are all incompatible is just a nightmare.
In 2001 I gave a talk (I believe at OSCon, to a packed audience) titled "Why SOAP Sucks". I started with a print-out of all the specs required to implement SOAP fully (there were lots of incomplete implementations around at the time, but barely any complete ones). It was more than two reams of paper (around 1100 pages of spec, if I recall). It had quite an "impact".
IIRC, the Table of Contents for the SOAP spec is bigger than the entire XML-RPC spec, yet SOAP offers little practical advantage. Luckily many new RPC implementations bypass both SOAP and XML-RPC and are looking to REST. $deity help all of us who need to work with legacy SOAP, however...