While I really like the idea of serving raw HTML and CSS, I think that on the authoring side, a static site generator that ingests Markdown and generates HTML is a more practical way to go. I think writing raw HTML can work fine for small pages, and arguably it can be better than Markdown for pages with a lot of design elements, like landing pages. But for the typical blog post, or especially if the blog post has cod…
There are lots of different MD flavours, though. And even with Pandoc extensions you cannot really have an image inside with and alt text and title text.
I've got some older posts that use Jekyll's {% highlight %} directive, and I know that won't work if/when I change SSGs, but to me that's a small price to pay for not having to author those in raw HTML! :)