Rides that are popular in one park but not the other

i think Magic Kingdom gets more visitors

I went to Disneyland April 2013, and TSM had a 0 minute wait every day, as opposed to a minimum 30-45 in WDW.

We must just have good luck but in the mornings and at night when we walk into New Fantasyland we can basically walk onto Voyage of the Little Mermaid at WDW.

Both of your Magic Kingdom examples are located in Fantasyland, which is stomping grounds for families with small children. At Disneyland, Mermaid and Winnie the Pooh are located by some major headliners, which eases the stress on the waiting times. As for Toy Story, the major reason there is that you're looking at DHS's five rides vs the many you can find at DCA, with Radiator Springs Racers still the top draw in that park. It's the same reason Soarin has a much lower wait there too.

The difference between Fastpass+ and not?

All the above answers are right, but the demographics of the resorts play part of it. Disneyland has many more frequent visitors that tend to skip so so attractions in favor of the E tickets and other experiences. People that haven't been to Disney in while are more likely to hit more attractions than those that visit more often. Winnie the Pooh isn't something people want to go on every visit. The Disneyland version is inferior to the Magic Kingdom version, and Mr. Toad didn't get evicted for Pooh or anyone else that Disney thinks would sell more merchandise, so that's a factor, albiet a small one.

Little Mermaid suffers at Disneyland from being in the wrong place. It dosen't really fit DCA unless Prince Eric's kingdom is part of present day California. DCA has stretched the California theme with its improvements, but Little Marmaid isn't even close to fitting the park, at least not compared to the other atteactions. Alnd with no similar themed attractions nearby, little princesses are likely not to go to it except by accident.

Robert has the right answer.

Sorry if my numbers are off, I've only visited WDW during the off season (early fall)

Gadget's Go Coaster/Barnstormer (Mirror images of each other)
Disneyland: 5 minutes
WDW: 15 minutes

Indiana Jones Adventure/DINOSAUR (EMV rides with similar layouts)
Disneyland: 45 minutes
WDW: 20 minutes

Buzz Lightyear
Disneyland: 15 minutes
WDW: 5 Minutes

Star Tours
Disneyland: 30 minutes
WDW: 20 minutes

Jungle Cruise
Disneyland: 20 minutes (has anyone else noticed increasing wait times?)
WDW: 5 minutes

Once again, sorry if my numbers are off.

Soaring is over 2 hours at EPCOT and half that at DCA. On average, most rides are longer at WDW.

Comparing Indiania Jones To Dinasour is like comparing Rock and Roller Coaster with a coaster same track design, except outside and missing all the theming and music. They'd both be the same coaster, to an extent, but the theming makes them two different experiences. Disney could Retheme the Matterhorn to Frozen using the same show scenes they are putting in the old Maelstrom in Epcot, and they would be more comparable even with a totally different layout and ride system.Its not just the design, it's the theming.

I think it has to do with crowds in WDW vs Disneyland and how the park is set up. Disneyland, as great as it is, was not built for super large crowds. Their Adventureland is a bit of a nightmare logsically. It is a popular bottleneck.

Another piece of thought I would enter in is that Soarin at DCA always has a moderate wait (like 30 min at most) vs EPCOTs Soarin that is always over 1 hour.

A ride like Star Tours has a lot to do with capacity. I believe there are twice as many simulators at WDW than Disneyland. I think you need to look at each individual ride and it's circumstances (location, capacity, number of park rides, FP or not, etc.) to get a true picture. This isn't something that just one generalization will explain.

Rob's right, Star Tours has 4 cabins at Disneyland and 6 at Hollywood Studios.