By then, it's WAY too late. The only time a bus operator at, say, Carribean Beach knows a specific bus is needed is when a family has been waiting 30+minutes for an Epcot bus and is screaming at the third empty Typhoon Lagoon bus driver - who then calls dispatch and sends whatever they need. Why would I want to wait even longer? By then, a bus is on the way (hopefully).
My system would need some kinks worked out, but it would be real time. I walk up, I swipe each card of my family (like at a fastpass machine), and press the chosen-park button and DisneyTransport repsonds. If Disney can use a fastpass system, and can also sense when one area of the park is too crowded and add an event to pull people to a new area, they can make the bus-stop-system work.