Some discussions about this, and building on MediaWiki 's idea of wikitext (MediaWikiText - no CamelCase and many conventions worked out thanks to http://wikipedia.org - hundreds of thousands of pages in 22 languages - this is not something we are going to reproduce!) -- do we want/need to? 
http://www.metaweb.com/wiki/wiki.phtml?title=wikitext_standard
http://meta.wikipedia.org/wiki/wikitext_standard
See also: WikiMarkupStandard
There are some news in this direction. A WikiMarkupStandardWorkingGroup is forming.
The Moin idea of parsers as a plugin seems more powerful and flexible. In that way, you can use any markup you/your community wants, without changing Moin base code.