Maybe this is just geek privilege talking here, but I think that emphasis and block quotes in markdown are perfectly legible.

The link format is weird (and I never remember how to type it), but I feel like it's not too cryptic.

Only geeks really use NoScript. Or people who know geeks that put NoScript on their computer. NoScript breaks many non-geek websites as it is, and they have to have geek skill to fix those breakages.

Remember that we're talking about markdown being shown to people with noscript, something I highly doubt non-geeks are using.

Wouldn't it also be shown to people who merely have Javascript disabled?