OK, now I made http://wiki.debian.org/DebianWiki/Engine and http://wiki.debian.org/HelpMoveDebianWikiToMediaWiki also link back to this bug so users can better find this proposal in the BTS rather than opening a new wishlist. The pros and cons are already mentioned on those web pages. Just let this bug be a longterm standing request to compliment those web pages. No action required for now. Thanks.