There won`t be an XHTML 2 language it seems.
The XHTML2 Working Group charter expires at the end of the year 2009 and will not be extended. This is caused by different opinions within the group.

Most of XHTML 2`s progession will be moved to HTML 5. More information can be found here.
In the six remaining months of its charter, the XHTML2 Working Group wants to focus on making corrections to the XHTML 1.1 specifications

But HTML 5 has also some problems;

• Apple refuses to implement Ogg Theora in Quicktime by default (as used by Safari), citing lack of hardware support and an uncertain patent landscape.
• Google has implemented H.264 and Ogg Theora in Chrome, but cannot provide the H.264 codec license to third-party distributors of Chromium, and have indicated a belief that Ogg Theora’s quality-per-bit is not yet suitable for the volume handled by YouTube.
• Opera refuses to implement H.264, citing the obscene cost of the relevant patent licenses.
• Mozilla refuses to implement H.264, as they would not be able to obtain a license that covers their downstream distributors.
• Microsoft has not commented on their intent to support <video> at all.

And to even make it better, the future of RDFa is still unknown!

But it`s worth to mention that progess has been made with SPARQL. SPARQL is a query language for RDF data on the Semantic Web with formally defined meaning.
The SPARQL Working Group has published the First Public Working Draft of SPARQL New Features and Rationale. This document provides an overview of the main new features of SPARQL and their rationale. This is an update to SPARQL adding several new features that have been agreed by the SPARQL WG. These language features were determined based on real applications and user and tool-developer experience.