HW3 no longer includes radar (or ultrasonics for that matter but that is only relevant to EAP features).
Pretty sure that isn't correct. Well, HW3 NEVER included them. HW3, just like HW4 is a computer board with no cameras, sensor, RADARS etc.
It's whether the CARS include cameras, RADAR, ultrasonic sensors. My Model Y has all of them. In the newer Model Ys they just didn't install them, they didn't replace the HW3 board.
Short of dramatically more advanced (and resultantly much more expensive) cameras you won't be able to match the distance of human perception at some of the lighting edge cases (high dynamic range and low light vision without being too blurred from longer accumulation time). HD Radar is basically a great way to fill this gap with a relatively cheaper solution which has a different set of degrading conditions (ie the set of times that both radar and cameras would be effectively useless is much lower).
So, all you can say is that more advanced cameras and HD RADAR are better? Or I'm guessing, you really are just assuming this, since you really didn't add any details.
In all of the images of Tesla visualizations that I've seen, such as the one below, everything seems to be accurately classified. Higher resolution cameras nor RADAR is needed.
Take a look in front of you the next time you get on the road. Do you look at every car and calculate their direction and speed? Of course not. You tend to focus on small areas, not that far away. You may look into the distance periodically to see what's coming, but not continually. Do you always look behind your car? Nope.
Drive through a pedestrian filles street. Are you continually calculating if each person is going to jump out in front of you. No, heck, you couldn't even tell me how many people you have passed.
Human vision is a LOT less than most people think that it is. When you look at the architecture of the cones and rods, you see a high density in the middle, thinning to the side.
And that tends to assume perfect (or correct to perfect) vision, lots of drivers aren't seeing with perfect vision. Many are driving with "barely can see it"
I'm very sure that if I was driving a Tesla and ONLY had access to the camera views, that I'd be able to safely drive the car.
Just because HD RADAR can more accurately map, just because higher resolution cameras have more resolution, doesn't mean that they are required.
One of the issues that the vision team has had and Elon has discussed is too much information. It takes a lot more processor power/time to process a 4k image than it does a 1k image. You then have to look at the differences in output and many would be surprised to see that there isn't much difference.
Let's go back 20 years to the old NTSC 640x480 TV. Have you ever watched this? Don't you think that you could have driven a car using images of this resolution. I'm pretty sure that I could. I remember an ancient Driver's Ed simulator that had lousy resolution, but I aced it.
Too much information is detrimental