> I think it's eminently readable
This. And proper line breaks help a lot, too. There's a reason single line breaks are ignored.
> People have mentioned tables here, and...yeah, they're messy, ...
IIRC, the "original" markdown does not include tables. They've been added by GitHub (I think), because it made sense for them, and many parsers started to adopt. I agree they are not easily readable in "source mode". It helps to properly align stuff, though, but it's a PITA.