As I am a frequent transit user I have noticed many things about the buses etc.
One thing I've noticed more than others is people struggling to open the back door, for one reason or another.
My idea is that we change the current back doors to mirror those on the new trains. One button on one of the doors, one simple push and it opens, no holding a handle or waving to a sensor.
This will also come with a red light to show that it is locked and a green light to show it is ready to be pushed.