I’m not quite sure I get the benefit here, given that FCC is targeted at beginners. Many HTML5 features have been in use for nigh-on 10 years, I’m finding it difficult to see what benefit there is segregating out features that exist in most environments (and are now generally part of the standard toolkit). FCC uses HTML5 stuff where relevant without marking it off as special, why should it be marked as special? And how do you differentiate (beyond a few very obvious things like sectioning elements)?
I have to ask: why do you think explicitly showing differences between the version of HTML that stopped development in 2000, and the current version (the one in almost universal use) is going to make things clearer (rather than extremely confusing) for new learners?
Edit: re “New block level tags that replace Divs” - the new[ish] sectioning elements don’t replace divs.