I'd be amazed to see a great WYSIWYG editor for any wiki, even among commercial packages. I evaluated Atlassian's very popular "Confluence" wiki awhile back, and it took me all of 5 minutes to find several bugs in the editor. Likewise for the wiki in SharePoint 2007, which was far less powerful.
WYSIWYG doesn't mix well with powerful features like templates and parser tags, and I'm not optimistic this will ever be fixed. Look at today's issues in a similar area, application configuration. Some apps provide graphical control panels to change their behavior, like Windows and Macintosh control panels. On the other hand, you have MediaWiki and Linux requiring people to edit configuration files. The graphical control panels are easy to learn (just point and click), but for serious application management, give me config files ANY DAY. Config files can be saved, restored, version-controlled, compared, edited with infinite Undo, shared with other users, emailed, deployed to multiple computers easily, edited remotely via SSH, etc etc etc. There is currently NO WAY a graphical control panel can compete for serious application maintenance. (I'm aware that you can put a GUI on top of a configuration file, but these GUIs frequently modify or rearrange the lines that you didn't change... which makes diffs unreliable.)
Likewise, end-users have done great things with WYSIWYG editors like Microsoft Word, but I personally would never write anything large or complicated in Word (say, a 500-page book) because it lacks important features for seamless version control, typestyle management, search-and-replace by regular expression, document comparison, multi-author collaboration... even complex cut and paste operations. (I wrote the O'Reilly MediaWiki book in Docbook/XML with GNU Emacs and Subversion.)
I think the WYSIWYG problem for wikis is similar. A graphical front-end can hide the complexity and encourage end-user adoption, but it also makes the advanced features difficult to use (and too easy for end-users to break by accident). I think it'll be a while before both audiences can be served excellently.
DanB
-----Original Message----- From: Sullivan, James (NIH/CIT) [C] If the wysiwyg editor future is not resolved for Mediawiki soon I'm afraid we will be forced to move toward another wiki software, most likely commercial where wysiwyg has been around for years.....