Great article on Zimmer's coaching history and dynamic style
The big jump in defensive performance last year is not so much about Zimmer's scheme, as it is about Zimmer's coaching. Zimmer has said he wants good teachers as coaches.
In Dallas, Cincinnati and Minnesota, team defense improved dramatically in the first years under Mike Zimmer. The only exception was Zimmer's one-year stint in Atlanta, which was aborted with Bobby Petrino's quick abandonment which drew the expletive-laced ire of Zimmer - and for good reason.
But disguising coverages and being able to play either effectively on a given play is important, and that was not the case so much in previous years. It was often very frustrating to watch a quarterback skilled at exposing the weaknesses of the zone defense, such as Aaron Rodgers, complete seam routes effortlessly it seemed at one point, and at another take advantage of a big CB cushion to complete an easy out route for a first down.