I couldn't really tell the difference between the Disneyland Pooh and the WDW Pooh, aside from the obvious building/vehicle/landscaping difference. The "show" itself seemed nearly identical, although the sets are placed differently at Disneyland. Let's summarize the reasons why Disneyland's Pooh has a shorter line than WDW's Pooh, with a new reason thrown in that I don't think East Coasters realize;
1. Higher capacity. Disneyland's Pooh gets over 1,000 riders an hour with it's 6 person beehive vehicles. WDW's Pooh gets closer to 650 an hour with it's 4 person vehicles. Higher capacity, shorter line.
2. Disneyland has no Fastpass on Pooh. Without Fastpass, there is no stagnant Standby line. Fastpass makes longer, slower lines for those who didn't get Fastpass. It's a vicious circle really.
3. It's out of the way, tucked behind trees and greenery. Same reason why Country Bear Jamboree wasn't as popular at Disneyland.
And finally, here's something I don't think has been discussed yet, but is a big piece of the puzzle....
4. Pooh is just one of EIGHT traditional dark rides at Disneyland Resort. At WDW, it's one of only THREE traditional dark rides. There's simply not a lot of dark rides at WDW, and people still like dark rides in the 21st century. Disneyland just has a lot more dark rides, and by the time they get back to Critter Country the average Disneyland visitor has probably already been on 3 or 4 or 5 dark rides that day alone, and they don't feel the pressure to squeeze another one in to their busy day. Within a 10 minute walk of Winnie The Pooh, Disneyland guests also find these other dark rides;
Peter Pan's Flight, Mr. Toad's Wild Ride, Pinnochio's Daring Journey, Roger Rabbit's Car Toon Spin, Alice In Wonderland, Snow White's Scary Adventures, and
Monsters Inc. Mike & Sulley To The Rescue.
The only other dark ride options at WDW are;
Peter Pan's Flight and
Snow White's Scary Adventures. And that's not just the list for Magic Kingdom, that's the dark ride list for the entire WDW property.
That said, I don't think you could compare any of the other three Pooh rides to the Tokyo version. I've been on the Tokyo version, and it's very much a big-budget E Ticket. The other Pooh rides are solid C Tickets. Tokyo's Pooh ride is amazing, and is in a completely different class compared to the other Pooh rides. No comparison.