I don't know about this "marquee" standard in the context of this subject, but a team having a franchise quarterback unequivocally plays a determining factor in a great many free agents consideration of their next landing spot. Guys looking to win a Lombardi that is, players looking for their first big contract are going to be less choosy. But it isn't often the teams who acquire the most sought after free agents and "win" free agency so to spean go on to be the most successful and win a championship. The Chiefs brought in Dee Ford but they were already pretty stacked.
As far as the Panthers and Newton, Gerald McCoy who was an established division rival has gone out of his way more than once to discuss the impact of having a quarterback like Newton on the roster.