Eye contact is a big thing when driving at low speeds - if you don't make eye contact with a driver you can assume they either don't see you or are not going to give you right of way (e.g., if you're jaywalking). I can imagine moments of confusion at intersections where pedestrians are unsure what the AV car is "thinking".
Similarly with other situations where you might leave a gap in traffic for someone to make that left turn across your congested road (would an AV even do this?), it helps to see that other driver wave you across (even if technically you don't have right of way).
I'd love to see some kind of indication that a car is in autonomous mode. That would let others adjust their expectations.
Especially cops, it could be legal to be asleep/drunk if the car is autonomous!
That being said, it would be great if autonomous cars kept up with traffic. I've seen autonomous cars going 50mph on hwy 101 when other traffic is going 70mph, or 5mph over normal highway speeds. Not a great situation.
Similarly with other situations where you might leave a gap in traffic for someone to make that left turn across your congested road (would an AV even do this?), it helps to see that other driver wave you across (even if technically you don't have right of way).