An other example is discussions. I think, it would actually be nice if the MediaWiki software would be changed in that way that the 'discussion' page of each article had a more automated formatting, more like a forum, while still enabling the wikimedia-syntax. Outdated discussions could simply be hided and a rating system for comments (maybe similar to /.) could also work very well.
this seems to be one of the wikimedia summer of code 2006 projects
To enable more semantic and meta-data support, or a more data-base-like feeling for Wiktionary etc. there's being worked at the Semantic MediaWiki (http://meta.wikimedia.org/wiki/Semantic_MediaWiki). Looks very promising!
And there is WiktionaryZ too...
Felipe Sanches ( "JucaBlues" )