I generally don't even like syntax highlighting for Markdown. I find having the text jump around because it became bold or italicized distracting, and it's even worse when a header is suddenly a larger size and everything below it is pushed down the screen.

Markdown is simple, and I like working with it simply.

I suppose there is some value in having the more complicated aspects, like images and tables, checked for syntax so you can see if you've made a mistake, but I run a macro to generate those anyway, so I'm fairly confident in the result.