What no one has mentioned so far is that Soarin' is a GENTLE ride. VERY GENTLE. There is no rocking, swinging, or bumping. It is NOT a thrill ride and it makes everyone happy--you can tell by the way people swing their feet back and forth when they're on it (and you can see this when you're sitting in one of the lower rows).
There is a single-rider line for Soarin' at California Adventure, so unless they've changed the number of seats in each row, I would say it's likely they're going to have a single-rider line in Epcot as well.
The merchandise for Soarin' at California Adventure has always been pretty poor. The shop in DCA is not located as you exit the ride, but in a separate building across the walkway. A few pins, cups, t-shirts, etc. Nothing cool.
Considering the tons of merchandise they did for Mission space, there's a pretty good chance we'll see lots of great merchandise for Soarin' at Epcot.
Soarin' is a spectacular ride, one of the best thing Imagineering has EVER done, and it's going to bring a lot of people into Future World.
