I agree that they need to be able to do a bit of pre-planning by knowing which resorts would have the most/least traffic that day.
It would get pretty frustrating because you know what will happen; the first time they do it - people will get on the bus to their home resort and then ASSUME the ME driver will drop them off at another resort - they will go up front and ask the driver why he didn't stop at so and so. There will be so many complaints about I didn't know that they weren't going to the other resorts, etc.
Some people will find anything to complain about....or any way to make their trip more difficult.
But how could you go straight to the parks, unless you have checked into your resort to get your KTTW card?