> Decouple it a bit more from html
Is that really possible? I've considered it quite a lot in the past few years, but I can never get past the fact that it has become the universal markup language. Even markdown converts to HTML before displaying (so it can by styled with CSS).
I think it would be an exaggeration to say that there's anything "wrong" with XML, but there's a reason JSON has by far overtaken it outside of "enterprise" applications.
That said, in some ways XML is preferable for standards - particularly in that there's a standard way to publish a document type specification, and widely available tools for validating a document against such specifications. The somewhat experimental equivalents for JSON haven't really ever caught on.
Verbose might be a real issue because it takes more bytes to send the same message. But then if you care about bytes, I think protobuf is worth considering instead of both JSON and XML.
And no, XML is just as much a standard (in fact, a better defined one as a formal standard), and is still very much the default in most enterprise applications. JSON being more common in startup land doesn't make XML not a standard.
Atom was invented as a replacement because nothing could be salvaged from the multitude of original RSS specifications. See RFCs 4287 and 5023.