I'll start, having grown a city to 40k, it's low-medium quality and hovering at 20fps but at least it's consistent. I don't get huge amounts of stuttering unless I swap tabs from the game which I have to change my resolution up and down to fix. I've been having fun with it despite that and I'm looking forward to a smoother prettier experience later.
Traffic AI is way better, the Industries are much better integrated and freight rail being managed by the player makes it way easier to deal with because external trains aren't clogging your lines and trucks aren't in a long queue waiting to enter the station. I like that some citizens like to jaywalk more than others.
I still can't figure out how to flip one way street directions. I'd like the destination path view of a person or vehicle again. I'd like to be able to assign a stop sign to only two of the four directions of an intersection.
I wish for a way to capture 30-60 seconds of a simulation to go forward and backwards in Photo mode.