Well, sure. I'm not saying Biz is a miserable defender. I'm saying that Biz guarding a pretty stationary guy with a jumpshot (Hawes) is entirely different from guarding an actual perimeter big, like Chris Bosh or the recently-traded Rudy Gay.
Bosh is much, much quicker and his team takes advantage of it much better than the Sixers.
Rudy Gay is just terrible though and I'm glad the rest of the league is finally catching on.