For me the TACC is now completely unusable because it accelerates too slow. Now it leaves a huge gap when the car in front accelerates, and takes many seconds before following properly. People behind me get annoyed, blinking and passing me. So I have to turn it off and drive manually. Completely non-functioning for me. This was changed in some software update.
Before this, it was perfect for me, holding a very consistent distance/time to the car in front, just as I want it in dense traffic.
I guess you cannot find a setting that fits all people, but this should be selectable or possibly follow Chill mode. If they make this selectable for FSD owners only, I find it provocative, because it is unusable as it is.
Which model do you have? which computer? About how long ago did you notice this change? I have FSD computer model 3, the latest software. My car does the absolute opposite of what you describe, I wish it behaved as you describe. The only semi solution that I have found in heavy traffic is to limit the top speed to something like 5mph. This stops the headbanging style driving, but It's actually a pretty bad solution because people cut in front of you making your car stop anyway, but it's the only thing that might make TACC usable for those that get carsick.
Ultimately I agree with you though, if your car lets you pick non essential comfort settings, like how hard you want the fan to blow, radio station, etc. it seems like a no brainer to make a setting that would allow people on either end (carsick-Headbanger) to use TACC/AP (one of the main benefits to having a Tesla) in one of the exact situations where TACC/AP would be the greatest help/relief. It could be in AP Option menu:
Follow distance on AP Variability: Anti Carsick Mode/Smooth 1,2,3,4,5,6,7,8,9,10 Headbanger/Rage Driver
(for those that pick 10 (the cars current unchangeable default setting) there could be a small graphic of Angus Young head banging near the other icons on the bottom of the screen when AP detects stop and go traffic, and AC/DC could play loudly on the speakers, to let the driver really get into it)