I thought Fleck had said it the other way around, that they switched to a 3-4?
Or something.
3-4's were created, IIRC, to destroy the very popular and difficult to stop veer option, back in the day.
They're really good, often, at stopping a power running team, because more smaller, flowing guys (LB's and stand-up DE's) can run around and clog things up.
Wisc has run a 3-4 that does this type of thing, for a long time. So wouldn't surprise me if Bielema decreed "this is what we're doing this week, I know how to stop them, this worked in Madison".