If by "effed up" you mean it now works in a way that is actually really useful. Previously, all monitors shared a single space, so you couldn't switch between s

If by "effed up" you mean it now works in a way that is actually really useful. Previously, all monitors shared a single space, so you couldn't switch between spaces on one monitor without switching your others. Now all monitors have independent spaces, so you can switch spaces separately, and you can fullscreen an app on one monitor without affecting another. It's soooo much better now.