Many good points made above, particularly that AVs have many, many more inputs than human drivers, but aren't as good at making sense of it. A great advantage of connected cars could be their ability to communicate with one another. My radar or lidar can see a car across the intersection, say hi, exchange introductions, and then they tell each other what they are doing (e.g. we are both turning left, so nobody needs to yield). All that can happen in milliseconds with dozens of vehicles at a time.
AVs have to be able to drive the way human drive as a last resort, but they can be significantly augmented with capabilities that humans don't have like the ability to precisely measure distance and speed or to communicate complex messages with dozens of other vehicles nearly instantaneously. Overlooking all these enhancements would be a terrible waste.
Vehicle to vehicle communications is what gives you the ability to do advanced coordination of vehicle movements that will create greater efficiencies over today's driving.
That said... Driving with just cameras is not a last resort. It is the primary way autonomous vehicles can and should drive. Lidar and radar can't be relied on 100% as there are some common materials/paints that won't reflect the beams. You could end up with accidentally stealth objects that are otherwise visible to a visible spectrum camera sensor.
Nor can active communications or GPS be relied on because both are going to be prone to latency and accuracy issues. Not to mention hacking and jamming. In all cases you want a car that sees another car to rely on its cameras (and supplemental Lidar/Radar) over some other car telling you where it thinks it is based on its best time stamped communications data. The other sensor or communications data will just be supplemental data and in some case will have to be disregarded if the cameras don't agree.
And just like the human eye you get good accurate distance information by using two cameras offset from one another by a very precisely measured distance. Better than a human, a car can see in all directions at once.
Also, don't forget we have an entire infrastructure based on signs that are human readable... construction zones, speed limit changes, accidents, cones, flares etc etc. No way as a society will we suddenly pay huge amounts of money to create additional radio communications based infrastructure for what would initially be a very small elite.
The way you get widespread adoption is by making autonomous cars drive like people first. And before widespread adoption of fully autonomous vehicles, we should get widespread adoption of autonomous breaking.
With currently available technology, it should be considered a safety defect and design flaw that cars will allow their drivers to hit other things. Autonomous breaking should be as standard as air bags in the next few years.
Once people are confident that most cars won't hit other things, people or drive off a cliff, then navigation becomes more about pointing the car in the right direction.