Why is there no WYSIWYG editor?

WYSIWYG editor (What You See Is What You Get, such as TinyMCE or FCKeditor) are still not very suitable for editing Wiki content. Although we would like to have an intuitive content editor the available ones do not meet our requirements since it is very difficult to produce well-structured documents with such tools.

So what we ended with is "aided editing" - you still edit the raw source (which is a great advantage - produces clean, structured code) but the editor provides numerous buttons and wizards to make things a lot easier.