With a four-five hour drive time from Miami to Orlando, that's a total of 8-10 hours just in driving for one day. Then add in park time and it's just not feasible for a day trip. And I highly doubt there will be a lot of people who aren't going to either game who are going to Miami just to go to Disney World. When the Super Bowl was in Tampa, that was a totally different story as the drive to and from Disney World was more like a daily work commute in some larger cities.