Also, XHTML 2 tried to push people to tags with defined semantics like ARTICLE, SECTION, MENU, etc. Most of the tags exist now in HTML5, but their semantics were neutered in the transition.
It doesn't really make development harder, because the semantic tags are defined based on properties that aren't visible to a parser. So it doesn't matter whether you use them correctly -- no validator will be able to tell.
XHTML continued the spirit of HTML 4 strict, getting rid of presentational elements and replacing them with 'sematic' ones. Eventually, you were also supposed to combine it with RDF to embed machine-readable metadata into your documents (cf https://www.w3.org/2003/03/rdf-in-xml.html and https://en.wikipedia.org/wiki/XHTML%2BRDFa ).