You do understand why this is, right? It's not a difference in popularity.
(1) There's no Fastpass in DLR.
(2) It's an extremely slow loading ride - estimates I found show 720 riders per hour. Meanwhile HM handles 3000 riders per hour.
So - combine those two pieces of information, and if you assume a fairly generous 70/30 FP/standby ratio (80/20 is more commonly used nowadays), then you realize that only 210 standby riders are getting on per hour. So that hour wait isn't just because it's popular, it's because so few people can actually ride it. (Though I will tell you - when we were at DLR last month we did EE to Fantasyland, and the line for Peter Pan was 45 minutes, and every other dark ride except Alice was a walk-on, so the popularity is there in California as well.)
But you are right in that Disney is very, very unlikely to ever build a ride like this again - not because of any "WOW" factor, but because they consider rider capacity to be MUCH more important. Ariel's Under The Sea adventure is a very recent example of the dark ride that is not about "WOW", but is about capacity. Ariel can take nearly 2000 riders per hour compared to the 720 riders at Peter Pan. (It's all about the spacing of the vehicles - look how close together they are in the ride system vs Peter Pan.)
I think you are missing one piece of evidence. In
Disneyland there are 5 dark rides (Pinnochio, Snow White, Peter Pan, Toad, AiW) and 2 outdoor kid rides (Casey and Storybook). So, Peter Pan is 1 of 5 dark rides, and if you include Small World, Dumbo, Mad tea Party, and Carousel you are looking at 1 of 11 kid rides. Then you have Matterhorn for coaster. Then we have Toon Town with a Gadget's coaster and Roger Rabbit spin (another dark ride).
In Magic Kingdom, IF you include Storybook Circus, you have 3 dark rides (PP, Pooh, and Ariel), Small world, Mad Tea Party, Goofy, Dumbo. So PP is 1 of 3 dark rides and 1 of 7 total rides. Then you have 7DMT for coaster and you are done.
So tally up the totals... 7 dark rides in and around FantasyLand in Disneyland. 3 in MK - including Ariel which arguably isn't a "dark" ride but we'll include it. Edit: For those keeping score - 14 rides in FL and TT in Disneyworld. 7 rides in FL and SC in MK. So 1/2 the rides in more space.
The issue is focus. Its not space (MK has more space between Fantasyland and Storybook). What you have in MK that you con't have in Disneyland is Meet and Greet's, Shops, and Character dining. Snow White DR was converted to a meet and greet. Enough space for 2 dark rides in NFL was used for character dining and greeting. A space large enough for a dark ride is used for shopping.
Clearly a decision was made to focus on other items in MK. We all know that. But I think there is demand (nostalgia, different, whatever the reason) for dark rides. And MK just does not meet that need.
