I did like Alice before the image mapping and don't feel it was "lousy" (old perhaps but still very charming), but I do agree with your opinions on those implementations of the mapping technology.
I'm usually against the overuse of video screens and how they're taking over as a prominent show element. Examples such as Toy Story Mania (which I highly dislike) and even an otherwise great attraction like Gringotts to me are the wrong way to approach video use in a ride. Rides like Ratatouille and Toy Story Mania I almost see more as simulators on a track rather than rides. But I do make an exception here for the manner in which EPCOT's rides generally used video and what you're proposing. Sets and animated/animatronic figures still being the prominent showpieces, but with background and other scenery using projected elements for added detail that would otherwise be static or blank anyways. For instance (if done correctly) I would prefer clouds that move and even change shape to a static painted image of clouds.
And i'm rather liking how they've been enhancing the classic Disneyland dark rides with this sort of thing, Snow White I think was the first and came out looking really cool (love how the entire room in the mirror scene morphs by altering the walls).
While this doesn't really count as digital video mapping, a recent example of how important dynamic background effects are came to mind. Pirates of the Caribbean at WDW has been missing a lot of cloud and rain effects on the walls/ceilings for years, i'd noticed how bare and detail-less the backgrounds had been looking. But shortly before the refurb these effects were switched back on (at least when i rode in May) and the difference was night and day. It really upped the atmosphere and helped maintain immersion, disguising the boundaries of the building. These effects aren't achieved via video projection and there are now better options with newer tech, but the general idea is similar.
I will mention though that other than Pooh and Peter Pan, there aren't really any dark rides to upgrade, those are the only two there anymore. And Pan needs FAR more than some projection effects to bring it up to par (i'd guess not much can be done to get Pooh up to par with Tokyo without a rebuild and more space). For the most part I prefer Disneyland's 1983 Peter Pan (even prior to the recent refurb), as well as Disneyland Paris. Shanghai is now getting an entirely new version of the ride. And with Tokyo's Fantasyland getting an overhaul, I would imagine their Pan is getting an upgrade/overhaul or even a rebuild as well (theirs is a direct 1:1 clone of WDW's apparently).
