Honestly though, a 4.7/5 generally sounds good. If a 4.7/5 is near the (very) bottom of the distribution then it sounds like the rating system is quite flawed and should suggest to Uber that they need to replace it (perhaps with just a "would you use this driver again" question, and if no, then whether the cause was behavioural (e.g. odour or some form of rudeness) or dangerous driving), then rank drivers using this. Vice versa for riders.
If the /5 rating system was accurate, then 'good' drivers/riders should be ~3.5-4, excellent drivers 4.2+, and poor drivers 1-2. But since some people have different definitions of 5/5 compared to others the rating system ends up generally turning into a 5/5 for above satisfactory with no real issues, and random usage of the rest of the scale.
Or, even worst, that you'll need 13 5-stars to compensate for 1 ride with 1 star...
But since everyone got in their heads that anything lower than a 5 is somehow an assault on the other party, 5s are the "average" rating and there is no way to distinguish between average and good. You only know that he was bad enough to get dinged .3 stars over the course of his history with the app.
If the majority end up treating 5 as average, then you also have to do the same and go with how the majority ends up using the rating system, which in turn forces even more people to use that definition of ratings, and so the cycle continues.
If you hold 3/5 as your average when 5/5 is held as the average for most people, you're just hitting the driver with a "this was awful" effectively.
This rating scale allows for some form of categorisation of the levels of 'badness' of the drive (e.g. differentiating between dangerous driving and jerky driving, between rudeness and general discomfort), but doesn't allow 'above satisfactory' to be separated from good or excellent.
But perhaps that's what Uber is going for with the rating system; maybe their intent is that 5 is meant to be 'above satisfactory' and anything better than that should be a 5 + a tip? If that's not their intent then I have no clue why they haven't redone the rating system already.
Also, those categories are subjective as well. What's the difference between "bad" and "really bad"?
Mutual graded rating systems suck. That's all there is to it. Because no matter what, it turns into currency. "Yes/No" and then base a rating on that. Rotten Tomatoes had it right from the start.
Only time she didn't follow the rule, the passenger changed a lot of details during the trip (I don't have money, can we stop a while at some bank while you wait in the car?, Could you take me some blocks ahead?, and some other weird things). And even with she complying with those requests, she got one star in the end.
So, yes, passengers are also rated and some drivers take actions based on that.