It would be nice if we had full control of the email HTML code without the WYSIWYG botching things up on occasion.
It would also allow us to perform advanced functions that aren't available in the WYSIWYG editor.
I've got around it somewhat by coding things in html, then opening the file in a browser, then copying and pasting into the template. However the WYSIWYG messes with the code, pure HTML would be so much easier than dealing with the editor, the ability to switch between WYSIWYG and Source code would be optimal as most editors provide.

