There is a really simple but huge improvement by using markdown:
It is often hard to search for the exact same place of the markdown viewer in the markdown text. So I think it could be a huge benefit if it would be possible to automatically bring the curser in the markdown text editor to the same point of the markdown viewer if we click on it (maybe with the right mouse button?). If it could be even done in the background, it would be even better; so if we have the markdown viewer in full screen mode and click on a specific point, the cursor should automatically go there so we can write in pure markdown (and don't have to use the WYSIWYG editor).
This would be much easier to edit a text.