LOTS of things, but I also understand why the changes were made.

For example, I REALLY miss the visibility that older cars offered. Thin A, B , C (and D) pillars afforded MUCH better visibility than what we have now, much smaller blind spots and so on.

Of course, those thin pillars would literally collapse when a car flipped onto it's roof thereby killing the passengers inside. SO I like that the new pillars are just structurally stronger, and I also enjoy that side curtain airbags exist (should I ever be in a position to use one, I'll be glad it was there). But none the less I do really miss that visibility that they gave, feels like there should be a way to have it both ways. Perhaps move the side airbags into the roof like they already are in some cars, etc. Really just thinner pillars for better visibility is my ask.

Like most here, I have a decently strong dislike for light electronic steering that has no feel. BUT I understand that my wants as an enthusiasts consumer is not the same as the average consumer who really does enjoy the light but numb steering of most modern vehicles. AND I understand how much easier it is to relocate the steering wheel for international markets when using electronic steering. I just really liked the feel of a good hydraulic steering and am not wealthy enough to have driven the electronic steering systems that others say feel nice.

Real buttons and knobs are, in my opinion, making a much disserved comeback. Sticking everything behind a screen really just sucks but I feel like most newly designed vehicles these days do have separate climate buttons and such. It's kind of now the exception to put everything behind a screen.

I DO wish that they would/could actually do more with the screen. I want it to be able to do a true vehicle diagnostic, tell me what that engine light means, do a better job tracking all the sensors and pressers. Really, I want all my car's sensor data to be available through the infotainment screen so that I can get a much better picture of the overall health of my vehicle from the computer that's ALREADY INSIDE THE VEHICLE! Show me everything and allow me to decide if I want to look at it, I know most people won't but some will, and I do. But it's not as if Classic cars had this function, but none the less I want it. Please let my car's screen talk to my car's computer to get data and read codes. That is all.

Vehicles these days all have built in cameras, but so few vehicles have built in dashcams. Like Tesla does, please allow me to record the feed of the cameras that are already installed in my vehicle. Seems like a pretty brain dead feature add, they'd really only need to put in an SD card slot. That's not really a classic car thing though.

Here's a classic feature that ties back to my original point. The tiny triangle shaped windows in the front near the A pillar. Those should be able to swing open like in older cars, get some fresh air scooped into the cabin. Hard to do that with such a chawkny A pillar though.

I like backup cameras, I like Android Auto and (I guess) Car Play. I dislike the built in software in almost every vehicle on the road, but I don't generally make use of it so that's fine.

If there were 1 feature I'd add to a modern car, I think it would be a universal buss that's able to provide power and data connectivity anywhere in the vehicle. You could run it through the frame rails even. It would make modifications and wiring issues substantially easier to handle. Connectors would then be universal. Connect an AC pump, same connector as connecting a fuel injector. Just put it all on a universal buss and let the car's computer sort it out (like how real computers work, smartphone or printer it's all just USB). This universal connector should be shared across brands, brands should be required to make drivers publicly available, all car computer software should be open sourced so that it's secure and modifiable. But honestly, all that's a pipe dream.