System Quarterback

Just a quick question... if Mariota is considered an ideal QB for the system he runs... and that system has proven to be successful in the NFL... why not just run the system that he excels in?If the Bucs are running a traditional NFL offense then Winston is the way to go since he's the better prospect. However the Bucs can do whatever they want, so why not just do something that would truly excite the fanbase and run a Kelly style pro-spread? Is Kelly really the only person that can run that offense at the NFL level?I'm not going to be disappointed with Winston or Mariota, but taking Mariota only makes sense if the spread comes with him.