> when CSS 3 is broadly applicable -- when it mostly ain't necessary anymore
> to use "class" or "id" as a style sheet selector.

The only good reasons for dropping class from a style sheet would be
that you had designed your own markup language, or you are using simple
styling for which the semantic distinctions within the markup language are
already sufficient.  Heavy use of ID, or other means of selecting specific
elements, in a style sheet, probably means that the "style sheet"
isn't really a style sheet, but rather is the presentational attributes
separated out.  A real style sheet encodes a set of general rules.