Why is this a problem? To me it sounds like a it would be an advantage because you have everything you need to render it already built into the software.
Rendering is trivial. The issue is standards, and the DOM. No-one can write a Markdown implementation for the core of any major web browser in a form that is simultaneously acceptable to both their technical and political governance.
Best you’ll get is a plugin. Strictly arm’s reach. Translation only.
I'm not quite sure I understand what you are saying. Is the essence of what you are saying that it is hard to agree on a spec for the Markdown (and how it is translated to HTML or directly to DOM?) Or that this represents a technical challenge I don't understand?
