I'm happy that Mulesoft are getting on the "better, human readable API DSL" bandwagon. It's very important.
At Apiary we found that embedding one format (Markdown, for human-readable documentation) into another format (YAML, for structured parseable data) is hard for the consumer, tough for the text editors/IDEs/syntax highlighters and ultimately useless. That's why apiblueprint.org is PURE markdown, that displays well on GitHub, has great syntax-highlighting support in your editor - and is just as parseable (since we ship an MIT-licensed parser with it).
I wish we could've united on a single format, but I guess the stronger will win and a little competition is always good for the end-users.