I don't understand this decision at all. It's not like they will save money - they'll still have half empty buses going back and forth from AK and Springs to the water parks. Maybe less travel time, but still no increase in efficiency, and of course higher inconvenience for guests.
Seems to me that the easiest solution would be to dedicate some buses strictly to water parks, and consolidate resorts for pickup. This way there are less buses dedicated and they stay full.
- Route 1: SS, POR, POFQ, OKW
- Route 2: Pop, AoA, CBR
- Route 3: Epcot resorts
- Route 4: FW/WL
- Route 5: Monorail resorts
- Route 6: CS, ASR, AKL
The Epcot and monorail resorts could even have one central location for pickup, like Boardwalk and the TTC, instead of stopping at each resort. Same for Port Orleans and/or Pop/AoA. I may be wrong, but I think a family would rather walk across the bridge from AoA to Pop (or vice versa) to catch a bus directly to the water park than take a bus to AK then transfer.