Why not reStructuredText?
It’s used by the Linux Kernel, has the same benefits as AsciiDoc but a much better syntactic and semantic foundation.
I think RST is the future due to how expressive, standardized (including the tooling) and well documented it is, but having all three major light markup languages (MD, AD and RST) would be ideal.
In any case, I agree that Markdown is just straight up bad.