I think markdown's popularity comes from its simplicity. For things like bulleted lists, especially nested ones, I can just type an asterisk and keep going. The raw input is still very readable (for the most part) and adding formatting is quick and easy. For anything basic - such as chat systems, social media posts/comments, or quick note systems - I don't think anything more is needed.
Something like reStructuredText (.rst) is a similar alternative, but I think that if you're irritated by the limits of Markdown then rST isn't going to be any better. If you really want good formatting options, then LaTeX is the best I can think of at the moment.
I think markdown's popularity comes from its simplicity. For things like bulleted lists, especially nested ones, I can just type an asterisk and keep going. The raw input is still very readable (for the most part) and adding formatting is quick and easy. For anything basic - such as chat systems, social media posts/comments, or quick note systems - I don't think anything more is needed.
Something like reStructuredText (.rst) is a similar alternative, but I think that if you're irritated by the limits of Markdown then rST isn't going to be any better. If you really want good formatting options, then LaTeX is the best I can think of at the moment.