William says, "Don't unnecessarily multiply entities"
Maybe in a reference work or textbook you need more complex css & html. But Fiction has headings that appear in TOC. Every other text even if it looks like a heading or is a character quoting a poem or singing or the narrator quoting (very victorian) is automatically suitable classes of <p> and is created automatically from the docx automatic conversion to epub. I never format tables, so there are really classes only for
Headings
unbulleted, unnumbered, unlettered lists. The i, ii or 1, 2 or a, b, or bullet are explictly typed in the source.
images (usually they need height & width edited because I can't figure how to tell LO Writer image settings that translate to the css desired. Headings & body text level & lists all work.
The text that's not a heading or a list.
All headings automatically are in the TOC. I've never seen <blockquote class="something"> created ever.
I've tried tables and the HTML & CSS is as expected. Not very useful in ebooks.
Putting numbering, Roman numbering, lettering or a bullet in the "style" in the Wordprocessor may not work as expected on Kindle or all epubs. Explicitly typing the list prefix always works, automatic doesn't. Indenting (first and wrap) all works as expected with expected HTML & CSS.
Simple is best. I'll let the purists designing specs worry about the semantics. We test any new WP style in kf7 on DX & KK3, kf8 on KK3 & PW3, epub on Kobo, Mars and Sony PRS-350 (5"), KoReader, Aldiko Basic and Lithium. Android from 4.3" v6 to 10" v10. eInk from 5" to 10".
Probably for completeness we should check Apple's Books on iPhone and iPad, but we distribute to Apple with epub2 via Smashwords. Amazon KDP and Google play books get the same epub2.
If it looks roughly the same as WP screen on 4K monitor (we set page to about 148mm x 197.5mm to edit master for ebook) allowing for KF7 fonts, then we are happy. We check epub and KF8 both in default setting a naive user would have and "publisher" mode.
Then when 100% proofed (a gazzillion cycles and all proofing & annotation on a Kobo) a copy is made with formatting & styles changed for paper. It's styled & formatted in 2 page up 100% actual paper size on the 28" 4K screen. We'd change space between digits and units to smaller space. Obviously headings, footers, page numbers and Contents page with numbers. Might fix any unsuitable page breaks, pointless for ebook.
Then electronic "proof" on Elipsa as PDF (the file to be uploaded) as well as PDF viewer on monitor, because sometimes you might miss a style. PDF export from LO Writer. We aren't doing anything fancy enough to need laTex or InDesign or whatever.
No dropcaps, no small caps, no text flowing round images on ebook or paper.