I don't know enough about programming to respond to your concern over
XHTML 1.1 so I don't see any problems going for XHTML 1.0. Any
problems going with the "strict" recommendation, or should we stick
5. The only DIV to be created inside the main content will be for
admonitions, sidebar and highlights.
Why? That way you will not be able to control rendering of whole section
or titlepage for example. Current stylesheets wrap these structures
inside <div class="section"> or <div class="titlepage"> respectively.