I would also love to see markdown. But if this is too much of a breaking change, maybe just add shortcut keys to the existing editor. I noticed that there are already shortcut keys for bold, italic and headers but not much else. Could these be added (Would also work in combination with markdown).
The shortcuts with the current editor are very, very limited. We are considering a complete rebuild on the editor which will allow us to offer a lot more features (and markdown as well)