A rating for Uber is silly. It's just a ride to get you to A to B, having a five star rating system is what creates a situation where leaving a 5 star review i the 'only acceptable rating'
I think maybe it should just be a few simple questions that are yes or no, based on did the driver follow procedures, get you to your location, provide a suitable vehicle etc. Maybe these questions are randomised so you only get asked one or two, to make the survey quick with riders that get a low yes rate on a certain question, having that question asked to more future riders to rank if it really is an issue or not, the app could even let you filter out riders based on certain feedback criteria if something is important to you.