There is a very definite line between good and bad preshows. Rise, ToT, and Haunted Mansion all have outstanding preshows, but preshows have crept their way into a load of attractions, which isn't bad, but it has almost become overused which diminishes its effect.That's the difference between an amusement park and a theme park. A theme requires a bit of story behind it. IMO, people who hate preshows have the attention spans of infants and would be better off going to Six Flags or wherever where they can jump in a ride vehicle and GO REAL FAST HURR HURR. Brilliant preshows like the Tower's and MMRR's are wasted on them.
If it is my first time experiencing a ride, a preshow is always welcome because it's a storytelling device, but for crazed lunatics, like myself, that have been to every attraction at least a dozen times, sometimes you just want to experience the physicality of the ride.
My favorite memories at Disney were around a decade ago, real late when the parks were virtually empty during extra magic hours; it was amazing to walk on virtually any ride without a wait. But preshows inherently delay the time it takes to get on a ride.
RnRc is definitely a great example of a somewhat annoying preshow; the theming is light and it isn't all that interesting -- the main appeal is the thrill of the ride, so if you've ridden the attraction a dozen times, the pre-show does not have all that much value.
Concluding note: I think it sounds like I hate theming and story, but that's not the case. There is a place for everything, including preshows, but sometimes, they're obstrusive.