IMO, I don't think the majority of guests are concerned with off hours service.
I don't mind waiting a little more off hours or even in the morning. My primary gripe is how long it takes to get back to my room at the end of a long park day with a shared bus. Take the Epcot loop as an example. If I'm staying at Boardwalk, from MK I must stop at the Swan, the Dolphin, the Yacht Club and the Beach Club first. I know, I know....BW benefits outbound by being the last stop. But if this were "rush hour", I'm sure that a full bus at the Dolphin would go directly to MK without any further resort pickups.
I understand the logistics for having shared buses. But I don't agree that it necessarily provides better service.