I'm not seeing the problem with ECV/wheelchairs/strollers in gondolas. Frankly there is no reason to have more than a few token seats in them and most of the room for standing. That's what you see at Stone Mountain in GA or Uber Gatlinberg in TN. Granted those are larger, 2 car, single line systems, but the fact is you don't really need seats.
Loading an ECV or wheelchair simply requires a door big enough to do so and a space for them to maneuver directly into. Frankly if you have doors on both sides for enter exit, and limit it to one wheelchair or ECV per cab, it's quite simple. Make the doors essentially 1/3rd as big as the cab, which would be more than twice as wide as an ECV, and have them open wide on both sides as the platform. Then make the cab twice as wide as an ECV is long and simply let the ECV roll on as people stream out the other side. Have them roll straight across until it faces the exit door on the other side. Then have everyone else stream in around, preferably from a series of pre-prepared lines with just the right number of people, like any number of rides at WDW. Put small bench seats only at the front and back of the car, and most people stand to look out the windows anyway.
Provided there is no malfunction with the ECV, and the rider is prepared to go when the doors are opened, there is no way it takes longer than 20 or 30 seconds to load a 10-15 person cab with a single ECV/wheelchair. A little paint on the floor telling people where to park their ECV/wheelchair, part of the recorded message reminds them to set the brake, another to remind them to prepare to exit on the other end, and... wala... fast loading and unloading. One Cast Member is there to put people in the correct size line, one to move the ECV/wheelchairs to the correct line and help them if required, one on the unload side to help clear people and ECV/wheelchairs out, and one to monitor the whole thing for emergencies and man the big red OH $H!T button. 3 or 4 CM per station.
Even if you ran it one car every minute for safety, with 15 people per car, that's 900 people per hour. Assuming buses fit about 75 when squished, you are talking 12 buses an hour to match this capacity. A bus every 5 minutes. I've had buses arrive within 5 minutes of each other at WDW, but I wouldn't say it is anywhere near the rule and it can take more than 5 minutes to load a bus, especially if you are putting on two ECVs.
