Again, agreed on all counts. Unfortunately, however, while Markdown (any flavor you choose) is pretty great for writing text, it's really limited in the types

Again, agreed on all counts. Unfortunately, however, while Markdown (any flavor you choose) is pretty great for writing text, it's really limited in the types of formatting you can do, hence also the types of documents you can create. That leads you down one of two routes: 1. Massively extend Markdown so it can do a large-ish subset of what LaTeX can do, or 2. Slightly extend Markdown so it can do enough to be useful, but nowhere near what LaTeX can. I don't see a great way to do option 1 without making something that's nearly as complex as LaTeX. Option 2 doesn't seem all that great to me, except maybe as a gateway drug to LaTeX. Maybe I'm thinking about it all wrong here, but it seems like Markdown itself sits at or near some local optimum of complexity vs utility that's pretty strongly attracting in the sense that going too far away from that point makes you lose the thing that makes Markdown attractive in the first place.