Considering current problems with bold and italic I don't think this kind of advanced formatting is possible.
But what I think is possible is to show such comment:
// This it <u>very</u>important:
// Call <b>Initialize</b> before using this function.
// Note: <red>never</red> delete <blue><i>this</i></blue> pointer
as:
// This it <u>very</u>important:
// Call <b>Initialize</b> before using this function.
// Note: <red>never</red> delete <blue><i>this</i></blue> pointer
Note that some doc generators also understand this kind of tags in comments.
Nevertheless I think there are still lots of more useful features to include.