So obviously this ride is impeccably well-made and themed, and I'm not the kind of person to criticize a good-faith effort. But I think there's two key elements that could really transform this ride in the future if they decide to plus it or build a clone in another park.
The biggest problem with the ride right now is scale. Not the scale of the sets, they're gorgeous and huge and grand in all the right ways. But the scale of the ride vehicles. The issue is that when the vehicles themselves are so large (and there's six of them) it makes even huge rooms with huge sets seem smaller by comparison. It robs the guests of that feeling of grandeur, because the comparison point isn't a single person, it's a massive, 10-person teacup.
The obvious solution is smaller ride vehicles like Pooh's Hunny Hunt (5 person) or Ratatouille (6 people). However once that happens, the issue becomes capacity. Dropping from 10 to 6 passengers means 40% less capacity. For Tokyo, the answer might just be upping the number of vehicles to 8. 8 smaller vehicles could likely fit just as well as 6 larger ones, and even though it'd be more crowded in terms of vehicles, it would solve the scale issue and make everything else seem bigger.
Tokyo's version is probably too set in stone for anything more than that, but for future versions, it could be fixed without adding more vehicles. And the solution is this: Rather than spending 90 seconds in each room, spend 60 seconds in each room and add an extra 1-2 scenes in the middle to keep the ride at a substantial length. That would also help solve the second problem with this ride, which is:
The snow scene and disjointed transition to the mob scene. The snow scene itself is just too dull. It needs more action (for Tokyo, that might just mean some projection mapping, or another animatronic, since there's no room to expand). But half the room is just doors and a basic castle facade, which is not much to look at. It's fine if you're only gonna be in there for 30 seconds, but 90 seconds is TOO LONG to have so little to entertain you besides beautiful music. Then there's the sudden appearance of the mob with no introduction. That's solvable too, but I requires another scene.
My solution for a future version of this ride in another park would be:
1. Reduce the ride vehicles to 5-6 person capacities. Smaller vehicles helps make the whole experience feel bigger and grander.
2. Add something else visually stimulating in the snow scene. Just like anything.
3. Add a transition scene before the mob. Perhaps we leave the snow scene and head into the woods where we come across the mob and hear them singing Kill the Beast. Then we follow them back to the castle. We just need something to ease us into the storming of the castle.
4. Add another storming castle scene. This is where Mystic Manor as a model could really help. Have each of the six vehicles duck into a nook where a different storming moment is happening. Give the riders a chance to break away from the group and have a more intimate experience (and also a different one for each vehicle).
I don't thinks those things would be terribly cost prohibitive. A couple extra scenes would expand the footprint of the show building, but neither scene needs to be too big. And with the smaller vehicles, you could actually reduce the size of some of the rooms like Be Our Guest, without sacrificing them.