Awesome... I've known teams crawl into the play-offs as wildcards with 8-8 records in recent seasons so 7-4 looks good.
All Vikings ever needed was a close-to-average QB to keep the defence honest... Adrian Peterson is a one-man wrecking crew of a running game, but with people like Tavaras Jackson taking the snaps the defence could just camp out defending the run and rely on shit QB after shit QB not being able to hurt them. It really doesn't surprise me they are flourishing with Favre, old as he may be. It's almost certainly not the form of his life though, his mid 90s form was awesomely thrill-tastic, and it's not as if he's being asked to win games single-handedly now for the Vikings.
And yeah, Green Bay have handled the Favre "situation" exactly right at all stage I think (except for beating the Vikings earlier this year!); when a guy retires and you tell his talented understudy that the job is his after about 5 years waiting and learning, you can't exactly seize it back from him when the old guy un-retires and decides he wants one more season. Embrace the future, and hope his knees and elbows pack in