I actually think this was a great time for Bret Bielema to leave Wisconsin. This is not meant to be a slam on Wisconsin, but he's reached the ceiling there by reaching 3 consecutive Rose Bowls (not done in the conference since the 70's). What can he do in the next seven years that exceeds what he's done in his first seven? There's really nothing that he can do. Keep in mind that Wisconsin was a 6-6 football team this year if Utah State had a competent FG kicker. The Wisconsin fans, like any fan base, were going to get angry with Bielema when the team had their inevitable slide down to the mid-lower tier of the B1G for a few years. When you can't really compete with what you have already accomplished, it's best to move on especially if moving on means more money and a chance to be appreciated for accomplishing the same things again.
The surprise to me is that Bielema is at Arkansas and not at Auburn. I think Arkansas is a really tough job right now with Alabama and LSU both being top 5 national teams and residing in your division. Who knows if the Tigers were interested in Bielema, but the other division of the SEC looks a lot more open AND the bar would initially be extremely low with how poorly Auburn has played the last two seasons.