I don't know if this is just in the summer- but if you are at the MK until it closes, there is a bus for YC, BC, and BW and a seperate bus for Swan & Dolphin. I'm a teacher so I am there during the busy summer so it could just be when it is busy. Anyway, the line to get on the BW bus is outrageous while the Swan & Dolphin is always short. We take the S & D bus every time. It is an extremely short walk especially if you are at BW.
I do agree. It seems like there should be better bus service to those deluxe resorts. You can't beat the location though! I love being able to take the boat or walk from Epcot or MGM. I always stay in the Epcot resorts so I can't imagine what it must be like to deal with the bus service to all of the parks!