Peter Pan, Mr Toad and Snow White were/are C ticket attractions. If modern imagineers could pull off new rides similar to those (and not overhype them as something they aren't), I think people would be a lot more receptive.
Look at Little Mermaid. Aside from a small handful of decent AA's, it's a C ticket at best, and still manages to rank below a number of the classic Fantasyland C ticket dark rides due to artistic lapses. To make matters worse, Disney internally classifies it as a D ticket, but then they tried to market it more like an E to the public. So you've got this bizarre mess of an experience that mostly C or below, to a few elements from a D and a tiny handful of elements that fit with an E.
I'd consider the Mickey Mouse ride to be a somewhat more "successful" modern variant of a C ticket when judged on its own merits. But the problem is that it's a replacement for a far superior E, and Disney tried to market it as an E experience when it just doesn't deserve that designation by any stretch IMO. Had Mickey been designed as its own separate attraction in a smaller and more intimate building, AND marketed as a C ticket dark ride, I would have considered it a solid addition to their lineup. Its inclusion at Disneyland seems to have gone over much better.