I have been on four or five WDW trips with high school bands (sometimes with Universal thrown in the mix, as well), and although they are a lot of fun, to me they are NOTHING like a regular family trip.
You have no say over which park, which days, which time of day, and your time in the parks is cut short by the activites the band is participating in, like clinics and parades (going backstage, dressing, waiting around, etc.). Not to mention that transportation can be cumbersome, with time wasted waiting for stragglers.
Of course the trips are still a lot of fun (it's Disney, after all!), and the kids usually have a blast, but sometimes the constraints can be frustrating for a true disney-phile.
Not sure if that is any consolation (epecially if they are calling you telling you how much fun they are having!), but hang in there and keep up the other strategies mentioned!