One of the biggest complaints about OKW bus service is "erratic service." Whether it be waiting at OKW, or at the Magic Kingdom for example.
95% of the time, the busses are running On Time, and it's just a case of skewed perception. Busses at OKW run approx every 14-17 minutes. Because of the slowness of the resort, waiting at the bus stop, time goes by very slowly. However, the busses do run at those set intervals, and are dispatched on time from the hubs. Before 9:00am, all runs are pre-scripted. Drivers are assigned a particular route, and they stay on that route, running in a circle. After 9:00am, the OKW runs are Flex Dispatched as part of Magic On Demand... they are dispatched at the same intervals as the pre-scripted routes... every 15 minutes, typically on the 15 minute mark.
The other problem is when at the hub itself. For example, at Downtown Disney, a lot of OKW guests complain that they'll see 3 All-Star busses and 2 Port Orleans busses before they see one OKW bus. Well... this is how it works. All-Stars get a bus every 5 minutes. Port Orleans gets a bus every 7 minutes. Old Key West gets a bus every 15 minutes. Why? DEMAND. All three of those All-Star busses will be packed. The Port Orleans busses will be moderate... and the OKW bus will have a few people.
As someone from the inside who sees the daily ins and outs of Disney Transport... OKW receives decent bus service. Yes, the intervals might not be as frequent as the All-Stars, however, the bus is rarely crowded, with the exception of one or two runs during peak times.