You'll see this up coming season though..
Butler is already completely better than Brewer, I was never trippin about losing Brewer..
Defensively? Naw.
Re:
Brewer was the glue of the Bulls' starting line-up/bench-mob defense. His nuances in defense: cleaning up on rotations, bluing of ball-handlers, cleaning up on missed transition defensive-assignments, 1-3 cover-assignments, tying up loose ends etc etc; made him a more versatile defender in comparison to Bogans. '11 season - Brewer led the league for team defensive efficiency (player on floor) and he led the league in biggest differential, team defensive efficiency; player on floor +/- off floor as well.
Defensive players with Brewers' mental/physical tools are certainly not easy to replace - Thibs' system included.
Jimmy doesn't yet have the defensive versatility, experience and intangibles that Brewer possesses.