When our group is larger, we will rent a car and drive to the parks, so during the summer months, I really don't take the bus that often, but when I do, it just seems that the bus that you are waiting for is always the last one to show up. I know about the bus routes, etc, but sometimes, especially during off-hours, like in the middle of the day, I think that they could combine resorts and run a little more often. It really is those waits that seem so long.
Plus, another thing that was not too nice was the fact that the busses do not go directly from the parks to DTD. It was really a pain having to backtrack to the resort to get a DTD bus.