Technically, Wade got more production out of those guys than Parcells did. Parcells might have been tougher on them but he stuck with Zimmer as a coordinator learning the 3-4 on the job.
Ellis, Ware, and Bradie James got better production but key building block investments like Spears, Hatcher, and Spencer underachieved and Ratliff remained out of position until the bitter end.
We've seen how hollow stats can be, especially when a few stars produce all the numbers and the rest of the team sucks. Dallas led the league in sacks in 2008, but teams did not fear the Cowboys as an elite defense. Hatcher, and Spencer finally broke through in 2012. Spears was a lazy fuck most of the time he was here, and I can only imagine Parcells constantly riding him would have made him better.
We're talking about two 1st's and a 3rd round pick here. Hatcher and Spencer proved they had the talent, Wade just couldn't get it out of them like a contract year could.