When Forbidden Journey opened many people, on many websites, said "Forbidden Journey is kind of comparable to Spiderman and The Simpsons."
Obviously they aren't the same ride systems, and they are different. I do agree that they do have some parallels besides just having screens. Physical sets overlapping with screened sets, physically moving from scene to scene, use of elements to increase story, etc.
Obviously those parallels show up between multiple attractions. Point being, all rides have some similarities.
Also, where did we get on the notion that a Gringott's coaster would be similar to Mummy? Even if it goes backwards I'm sure it'll be VERY different from other attractions in the park. Starting with the fact that I doubt Premier will manufacture it.