A nice (premium) feature that Byword has is blog publishing.
Essentially this allows creating your blog post in markdown and then publishing it out to Wordpress, Tumblr, Blogger or in fact, Evernote (which perhaps whilst not a blog publishing platform is quite a nice export).
I don't know how feasible this would be to add to markdownpad, and it would seem a good candidate for being markdownpad pro only, but it would be a useful feature to have.