Generally per passenger mile monorails are much safer. Buses hit people, cars, trucks, barriers, other buses all the time. Drive back to the Monorail shop, the ground floor on the East side is bus maintenance. Off to the side are the damaged buses waiting for repair. Sad.
Monorails are grade separated so generally no one, car or bus hits a monorail. Technology can make things even safer with active train tracking so the dispatcher knows exactly where every train is. Adding an catwalk between the tracks is not difficult, most new mass transit monorails have these. So you can just walk to safety.
The real transportation problem at Walt Disney World is balance. The large bus terminals at each park are there partly because Disney didn't expand their Monorail system. Disney only bought buses because they are cheap solution to a growing Resort. At the same time Disney should have also added more Hotel boats and Ferry Boats and added an East-West Monorail line. This way if one mode is experiencing a problem the others can take up the slack.
Today - Certain times of the day the road in from of the Contemporary is total gridlock and the water bridge tunnel limits any widening of the road. DTD is also gridlocked with cars and buses the solutions is better boat transportation for the DTD area hotels. Add a monorail to take some pressure off the roads and buses with quick service to Typhoon Lagoon, EPCOT (MK areas), EPCOT Resorts, MGM, Blizzard Beach, Animal Kingdom and the AK Lodge. It's not financially reasonable to run a monorail to every hotel but to have area stations is logical.