I think it would be great to support Markdown, fully, in the core installation without having to download a plugin for it.
It would be a great way to ensure people can get going faster if Markdown was added to core.
No, but I can write accessibility tutorials, though.
I think it would be a mistake to have Markdown by default, since the majority of people don’t know about it and would have trouble getting their * and _ and > to render the way they intend. Also, any syntax with square brackets can make shortcodes more difficult.
Not to mention there are several flavors of Markdown and you’d have to choose one for everyone.
Good points. Also, why add things to the core that can be a plugin on their own?
All this add everything to the core is what made WP such a bloated CMS.