DOM Dynamic pages scares a lot of people in accessibility land,
but there are also strong potential once document guts are exposed. We
need to understand this technology very well in order to see if best
practices alone will be sufficient.
XML
Less about making XML accessible per se than defining a WAI XML namespace and
collection of attributes (with HTML4 semantics as basis) to translate
accessibility features into any other DTD.
XSL
Whatever is too sophisticated for a CSS generation language:
e.g. Tree-transformations in service of adaptation and alternative
content flow as an adaptation technique.
CSS3
Whatever didn't make it in CSS2 and is not of the XSL kind. Braille CSS
probably up.
RDF
Making sure there is enough LINK and META enhancements to ensure that
dictionaries, including data dictionaries, can be TARGETed to an
arbitrary HTML container element.