XSLT 2.0 provides much easier-to-use grouping facilities, but it still doesn't allow for dynamic expression evaluation (that is, expressions constructed at run-time as a string, or read from source documents. You still need extensions such as saxon:evaluate() for that.
But as I think Joe mentioned, so long as you're using XSLT client-side you have to wait for the browser vendors to supply the technology you need, and since no-one is making any money by selling browsers that can take an increasingly long time.
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference