Editor's note: The following story is a part of the 2019 Cowboys/NFL preview section, which will be included in print editions of The Dallas Morning News on Thursday, Sept. 5.After reaching the divisional round of the playoffs last season, the Dallas Cowboys are thinking Super Bowl this year. Nevertheless, Lombardi Trophies aren't hoisted on the back of preseason optimism.If the Cowboys want to realize their dream of a sixth Super Bowl victory, they need to be vastly improved over last year's team.