Heh. At work, I deal with most of the wiki engines anyone has ever heard of. Let me assure you: *all* the various wiki markups are horrible, and I don't think any of them were "designed" per se. MediaWiki's is, I understand, provably impossible to put in EBNF, which is why the parser documentation is the parser code ... But it's not actually worse than any of the others. Though possibly it has more odd bits bolted on the side.
Good point, and sorry for just repeating it in another email.
Wiki Creole is simple enough so that you can have an EBNF. The benefit of this is exactly that you now are independent of a specific implementation. If you wanted to write an alternative editor or engine you can work of the specification and discuss this rather than having to use a life instance to check whether something is valid wiki markup and what is meaning is.
DIrk