Yeah, definitely agree. I think the advantage of radar wasn't so much related to visualizations, but rather the ability to potentially know if an occluded car suddenly slowed down. It allowed AP to reduce speed even prior to the car directly ahead hitting the brakes. That is a fundamental sensor physics thing that vision cannot compensate for. You can't react to what you don't see.I believe that the remembering and predicting part, i.e "temporal continuity and extrapolation" is exactly the most exciting benefit of v9, and by extension all the similar, though possibly hastily-constructed, updates to various other AP features.
The improved stability seen in the visualization is probably evidence of this. There are ways to achieve a more stable display without really reflecting a fundamental improvement in NN confidence, but I don't believe they're just playing display games with us; it makes perfect sense that the temporal analysis would have this stabilizing effect.
Regarding the radar-sees-past discussion, I again want to caution everyone against over-hyping that radar capability, and by extension being overly mourning its removal. The radar cannot "see", identify classify and track a lead vehicle just because some microwaves scooched under/around the in-between car and the reflection scooched back again.
Yes it's wonderful to be alerted that "there's something up there and it's suddenly stopping" - but that's about all the info you get. I'd be cautious about the idea that it would draw a box and track it reliably; that is probably more effective from the advanced camera NN catching glimpses as a human driver would. And if the system is aware, from glimpses, that the immediately-in-front vehicle is following a lead vehicle too closely, then it should adjust its own following distance in defense against a possible pile-up - the same way a smart and experienced human would. I'm not denying that the radar could help out here, just saying that its output is far less detailed than people are implying.
I think it is fair to not treat radar as a silver bullet when it comes to AP/FSD. But, at the same time, radar is a fundamentally different type of sensing modality with inherent advantages over vision and it seems silly for people to start pretending like that isn't true any more. It certainly has plenty of drawbacks as well and Tesla has obviously had a hard time with sensor fusion, but it feels disingenuous to pretend like it isn't still fundamentally superior to vision in a small subset of situations and that no amount of vision-only improvements can replace those abilities of radar for the simple reason that vision works in a different region of the electromagnetic spectrum and the sensors work differently.