The thought of only special, out of the ordinary rides getting a 5/5 is amusing to me. That's absolutely not the culture I want to experience as a rider. Even above-average levels of conversation can be distracting when I just want to quietly think about what I'll be doing at my destination. My ratings are basically either 5/5 or 1/5.

regarding 2), it's certainly fine if all you want is a ride from A to B, but there are plenty of other things that meaningfully improve the ride for me. maybe the driver is actually familiar with the area and knows a faster or more pleasant route than the one google maps picks. maybe it's a long ride and you have a genuinely interesting conversation that helps pass the time. maybe it's a hot day and they have bottled water in a cooler. maybe they have a much more comfortable car than you expected.

there should be room to acknowledge people that go above and beyond the requirements of their job without being punitive towards the people who do a fine but unremarkable job. I tip most drivers who don't completely fuck up the transportation part of the job, and I tip extra for really good rides, but I wish there were a way to recognize this in the ratings too.