I> might be wrong, but I believe there's a legal implication to doing
something like this (at least on WMF wikis) since it's removing attribution to various people who "contributed" to the article, even if it's not in the traditional sense. Also it kind of violates the basic design of MediaWiki itself, which is to keep revisions of pages.
This would make an excellent extension though. I know we would use it. It's probably one of the most straight-forward to make extensions I've heard of as well.
Thank you, Derric Atzrott