> If what you are saying is "the canonical form should have common renderers", then HTML would be preferred over XML. However (avoiding all caps there, but barely), you are assuming that the CSS associated with the canonical format is either part of the HTML file itself or that the HTML has a normative link to a static CSS file. Is that really what you want? This will very likely lead to errors if the CSS makes either vertical or horizontal spacing issues that are not easily detected by authors who are only looking at the rendered version.
Hopefully the spacing isn't semantically relevant...
A good way to smoke out such problems is to review the document using a different layout than used during writing. For instance, the RFC Editor could present a PDF rendering during AUTH48 review, with margins etc that reveal common mistakes.
> Anyone can read XML if it is formatted for reading.