Does the 'history' function maintain separate forks? I haven't really looked at it, but it doesn't seem to really jump out at the user. When I read a wikipedia article, I see only one text under a title at any given time. I can't choose between different competing articles.
What I am suggesting is something like this: when a user looks up, say, "Abortion", they are presented with a listing of high-rated articles to choose from, probably with a summary or something to help them make their decision about what to read.
Wikipedia is a collaborative project. With this system, articles would not be of as high a quality. Your not considering quality over quantity. Why have 10 good articles to choose from when you can have one excellent one?