It's really, really hard to repeat as Super Bowl champs for one reason: it's really, really hard to become Super Bowl champs. Most of the time it comes down to just a few plays. The margin for error is so small that one bad break, one call, one strange bounce can mean you're season's over.
Don't worry about "distractions" or "desire" for the upcoming season. Worry about key injuries, bad calls, or a few plays where the team doesn't execute. That's what will keep the Saints from repeating.