While I could see your point, one instance of projection mapping not only updated a ride, but made it more iconic, that being Alice at DL.
I think, what needs to be done to make it work, requires the indoor scenic design to be gutted, but with keeping the ride layout intact. It'd give them the chance to use all available space possible, along with giving a fresh start for the possible implementation of Projection Mapping, it'd be a chance that could benefit the attraction in the long-term game.
It just matters, to how effective it can be used.