I also plan on experimenting with new editor features via browser extensions.

So instead of adding a Markdown preview in the editor, you can install an extension that'll show you a preview when you click it. Instead of adding a @snap_as uploader, there'd be an extension that lets you upload files and get the Markdown back, or see your existing photos and click one to insert the Markdown into your post.

Just ideas now, but the goal is adding functionality without cluttering up the interface.