[...]As I've said, that implies that the writer is capable of crafting their own epub. I doubt most colleges' creative writing programs have the inclination to devote a section to writing CSS HTML, and Creative Writing majors aren't allowed into those classes anyway because of degree restrictions and course prerequisites. What most authors do know is Word, even if they don't have any formal training in it.

I don't have anything too fancy in my writing, so removing the bits Smashwords doesn't like (if I ever decide to try them out) looks like it should be pretty simple for me: a quick macro and everything done in a minute or two. Removing stuff is easy, putting it all back in - correctly - is much harder, and so I am much less confident that Smashwords can exactly recreate what I went to a lot of trouble to create in the first place.

I am not sure why you are insisting on hand-crafted epubs. I find that Writer2xhtml (google Writer2Latex) creates reasonable epubs from my OpenOffice files. There are other options too. The only hand-crafting may be a few meta-data things later - the sort of thing than sigil could help with. None of this seems too far out of reach of most people capable of using a word-processor.