I'm not really a believer in windows. That whole point of the draft and free agency is to always be adding talent so that as some players age others are stepping up. Of course, adding talent doesn't automatically eliminate ups and downs, but there shouldn't be dramatic or long term swings downward. Obviously a team needs to have some draft success, which the Cowboys generally do pretty well, but key free agent additions can be a notable part as well, and that's an area the Cowbys generally don't do well.
