S stands for simple, dans ce dialogue imaginaire Pete Lacey a brillament regroupé tous les arguments qui expliquent pourquoi d’ici 2-3 ans toute la stack SOAP/WS-* va subir le même sort que les EJB 1/2. On va tout jeter à la poubelle et standardizer à la place ce qui marche déjà à savoir des documents XML (ou autre) directement sur HTTP, bref REST.
Juste un extrait du dialogue qui résume bien le caractère schizophrène de SOAP/WS-*

[…]

Dev: Well, I could mostly make things work, but only if I stick with one SOAP stack. Also, I can’t say I like the idea of remote procedure calls and serializing objects.

SoapGuy: Remote procedure calls! Serialized objects! Where did you get the impression that SOAP was about RPCs? SOAP is all about document-based message passing, my friend.

[…]

Dev: Reflect on my code? I thought it was all about documents, not serialized objects.

SoapGuy: Didn’t you hear me? It’s all about the tools. Anyway, we can’t expect you to write XML Schema and WSDL by hand. Besides, its just plumbing. You don’t need to see it.

Dev: Whoa, back up. What was that word? Wizzdle?

SoapGuy: Oh, haven’t I mentioned WSDL?

[…]

(via Loud Thinking)

Mince, avec un peu d’avance  (décalage horaire oblige) Tim Bray a écrit un billet très similaire. Bref, il faut vraiment le lire ce dialogue!