While I hesitate to say never, I am going to go out on a limb and say we won't be seeing any monorail expansions. It is just cost prohibitive. Also, as I have said in other, similar threads....it is next to impossible to get passengers off the monorail if there is an emergency. I have been 'trapped' on a monorail, for 35 mins..just sitting there, waiting for the track further up to clear. It was awful. Hot, humid, jammed with people, many standing up. Kids started crying, parents are yelling at the kids. It is not something I want to experience again. I love the monorail but it is limited in what it can do.
Buses, as someone already noted, can be routed wherever they are needed. I truly don't care what the buses look like...I'm riding on it for about 30 mins, not buying it!!! It's public transit..plain and simple. Sometimes the buses are full and sometimes you get personalized service and get to ride all by yourself. That's the nature of 'public transit'. Disney does an incredible job of moving guests around. If a guest prefers a quicker ride, then they are free to go out and rent a car.
I'm thrilled there are more buses coming on line, with drivers to drive them. I truly think the WDW bus drivers have one of the hardest jobs at WDW. They take an inordinant amount of crap from guests. I see them getting yelled at, criticized, berated. And yet, most of them remain pleasant and helpful. Nope, I don't care what color the buses are, or what design they may have. Give me helpful, happy drivers.