Like many, I feel that the poster is throwing the baby with the bathwater. Yes, SOAP and XML Schema are horrible. Don't use them, then. Yes, XML is verbose, but that's exactly why Relax NG has a compact syntax. Use that if you don't like the XML syntax. Yes, data can be expressed as attributes or elements, but there are simple rules of thumb to decide between one or the other: if your data can have structure, or you may want to have multiple instances of the same thing, it's generally better to use an element; otherwise an attribute should do the trick.

There are also errors and approximations: XML did not introduce the bracket syntax, it inherited it from SGML. A DTD is not a schema (and if you want to criticize XML, you should point out that it should not have inherited DTDs from SGML.) He doesn't even mention the worst part about comments, which is that you can't have -- inside a comment (very annoying when commenting a large block of data...)

XML has many beautiful applications, like SVG, SMIL (which never took off but keeps getting rediscovered/reimplemented in an inconsistent manner [full disclosure: I participated in the SMIL and CDF W3C working groups]), XSLT, &c. XHTML was not perfect by a long stretch but the new HTML5 syntax is much, much worse.

Use XML, JSON, and whatever is necessary to get the job done. For the project that I am working on right now, I am using XML for serializing Web app descriptions; in this situation, XML is clearly better than JSON.