[Animats]

The trouble is, people keep extending Markdown to add HTML features. There's even Javascript embedded in Markdown.[1] You'd just create churn, not a fix.

[1] https://www.markdownlang.com/advanced/javascript.html

[OkayPhysicist]

There is no "adding HTML features" to Markdown. Markdown is a superset of HTML. You can simply put HTML tags (including script tags) in your Markdown.

[Animats]

If you interpret Markdown that way, all you've done is encapsulate HTML and JavaScript. Nothing gets simpler.

[trumpdong]

Exactly the problem.