First thing to note - the monorail and the platform are not at the same level - there is a step up from the platform to get into the monorail.At Disney you've got a wide variety of wheelchairs and scooters which are in various sizes so you can't as easily design a one size fits all loading system when the items loaded are going to vary. I think that's the reason they always pull out the actual ramps to that a wheeled device can be wheeled on without having to worry about wheels getting suck in the cracks between the train and the loading platform.
As someone with much experience with an ECV and Disney monorails, there are a few issues with the Disney monorails and their ADA ramp system:
1 - the ramps are put into place manually by the operator, some can do it quickly, some are much slower
2 - the width of the ramp only gives 2-3 inches maybe on each side when an ECV is pulling into and backing out of the monorail car
3 - the angle of the ramp is somewhat steep, and if the ECV driver isn't used to the ramp, especially when backing out, it can slow things up
My suggested solutions:
1 - make the ramps wider
2 - make the ramp longer? so the angle isn't quite so steep, ideally the monorail would be the same level as the platform, so if a ramp was used, it would be level and just be a means of covering the gap
3 - wishlist, blue sky item! Have a few cars on each monorail that have a turntable in it so that the ECV or wheelchair doesn't need to back out, the turntable would turn it around!!! HA!