The defense is what got Wade fired. The defense sucked the 1st half of that season and Jerry fired Wade because of it.
How many years did people here complain about Ware's "empty" sack stats. Every year there was a horde of people saying that Ware didn't get sacks when they really need them but racked them up in garbage time. Spencer was almost universally hated for not getting enough sacks. Fans constantly complained that Ratliff was too small at NT and fans wanted "more beef" in the middle. Every year some at CZ would propose going to a 4-3.
All of those complaints don't happen if the D was great.
Look at Romo's stats over the years. It seems almost impossible for a team to not win big with those stats unless the defense was a problem.