This is a good experiment on many levels. Facebook has more readers than Wikimedia, and it's possible that the overlap is not significant. So if there's a way to reach more readers through Facebook and encouraging new participants to come to Wikimedia, then that's a good thing.
That said, you're right, a lot of things have to continue to change if we're going to take advantage of this. Hopefully, a partnership like this will help catalyze change.