The world has gone SOAP mad. I've been working with XWT and I recently came across XUP from MartSoft.
"XUP is a protocol for delivering events and user interface updates. It is independent of the actual UI or event model. It places no restriction on the UI component set, or the attributes or events associated with each component. Furthermore, it supports both delegation and capturing/bubbling event models."
"XUP provides a model that bridges between the traditional desktop based and web page based user interface paradigms. With XUP, events are delivered from user agent to server as SOAP messages. Programmers implement event handlers on the server side. They no longer need to process form data as URL-encoded strings. User interface changes are delivered from server to user agent as incremental updates, so end users will no longer experience slow page refreshes, and network bandwidth is conserved."
While most of this can be achieved without SOAP I guess the industry's will must prevail. I also think that relying on the network for user input/output for responsiveness and consistency is mad.
As the note says:
"Because events are dispatched over the network, to conserve network bandwidth, the user agent should not send certain types of high-frequency events, such as mouse movement and key press."
While the specification doesn't dictacte the UI model they do mention XUL an awful lot.