(I should add, for the benefit of any Microsoft coders out there: if you don't get support MathML and SVG in IE right soon you'll end up displaying GIFS and loading klunky Adobemedia plugins when the rest of the world is dragging and dropping formulas and vectors, not to mention serving all this stuff inline
Should I get worried? Well, I know all this stuff, so no. Also, it is still easy to get started. You don't have to know HTTP to know HTML, which is the substrate upon which the rest is built.
Anyway, this leads me to the conclusion that a) dumping XML on the client for transformation is not intrinsically wrong, b) JSON-RPC is nice, c) passing HTML clips via XMLHttpRequest is not an ideal situation but works.
Also, despite me not working on Gradient for ages, I still believe that the web is missing a real-time control channel and the ability for clients to communicate more-or-less directly with each other, and that XMPP is the solution to that.
What's changed is that Firefox 1.5 supports SVG now... I'm thinking of digging up the old and obsolete JiM or fiddling with Mozchat and seeing if I can wire either of them directly into the DOM.