Have to agree with Teebin on this one. It can still be a family ride while having Mummy's height restriction also. More thrill and fun for all, where's your harm in that. If you really wanted a more tamer experience or something all the family can enjoy, I'm sure the new Hogwarts Express will suffice just fine. Hopefully they add a great walkthrough attraction too.
The harm is in the 48 inch height requirement. Nothing about that is 'family' friendly. It can be thrilling but they are going to want a vast audience. Forbidden Journey was already pushing it at 46 inches. Like I said. Expect 40-44 inches. The bigger the audience range the bigger your profit. The thrill will be in simulating danger for the most part. A Spiderman/Dinosaur/Thunder Mountain level of thrill. Universal already has enough 48-54 inch rides.