I love the editor, but it's not quite WYSIWYG. It's a Markup editor. The key difference being that you still see the "code" as you're typing it, not the way it would be displayed.
WYSYIWYG is more of a "Word Document" style editing, where you hit the bold button and your text appears bold as you're typing it. Wikispaces uses this type of editor, which is why my current employer prefers to use them instead of this for a wiki system (I shudder at that). I'd love to see this go in as a fully WYSIWYG editor to make this just one more reason to move everything over to bitbucket.