It makes sense in america since many of theme theme parks there have characters from films, but in the UK its a bit different outside of a few exceptions such as Mythica. Its the lack of knowing a rides narrative is what makes them so encapsulating and great. They can be molded by the guests to whatever they think of.
I'd argue that there are many ways in which you can build a clear narrative without necessarily spoon-feeding it to people. For instance, at Europa Park, rides like CanCan Coaster are wonderfully themed and tell a wonderful narrative through the beautifully immersive queue lines jam-packed with detail, and the scenery throughout the ride.
Taking CanCan as an example, that ride doesn't once put a video screen in front of you to physically
tell you a story. It doesn't even use boards to tell you a story. But that wonderfully immersive queue line jam packed with details and theming, and the heavy theming of the ride itself, tell an incredibly clear and cohesive narrative in themselves without necessarily needing to physically spoon feed you a backstory. Despite the lack of a video or storyboards, CanCan has an incredibly clear and wonderfully cohesive narrative that's conveyed beautifully, in my opinion; the theming and little details do all the storytelling you need.
It's similar with Wodan; that ride doesn't once stop you to physically tell you a story, but that queue line is so gorgeous, and such a work of art, that it does all the storytelling you possibly need and makes the narrative and theme pretty obvious without explicitly spelling it out to you.
I'm not saying that Europa Park is the level that Towers necessarily need to be shooting for (it would be unfair to compare Towers with Europa because EP is simply on a completely different scale, as well as a totally different type of park), but my point is that giving a ride a clear narrative isn't necessarily done by shoving you in front of a screen and physically telling you a story. The theming can be so, so detailed and wonderful that it tells its own clear story, and I'd argue that it's that kind of storytelling that Nemesis lacks. The monster and pit are impressive, but the ride lacks the little details to take the storytelling to another level.