The only thing that I'd like to see changed would be to allow a more flexible syntax for formatting codes - in particular, I'd rather use something analogous to the 'embedded comments' described in S02, replacing the leading # with an appropriate capital letter (as defined by Unicode) and insisting on a word break just prior to it.
I'd also prefer a more Wiki-like dialect at some point (e.g., '__underlined text__', '_italicized text_' and '*bold*' instead of 'U<underlined text>', 'I<italicized text>' and 'B<bold>'); but that can wait. Otherwise, looks good. -- Jonathan "Dataweaver" Lang