Did anyone else notice this? It seems that the big patch was supposed to improve the driving but I've noticed no difference at all.

I believe what it specifically did is add a game setting which you can change which applies to control sensitivity for all cars.

Previously control sensitivity only varied by car with generally the more expensive ones being more responsive and easier to drive.

You might need to go into settings (in game) and change this particular setting to see any difference.

The cars are also vastly more responsive at high and low framerates.

At more normal ~60 FPS, they would seem to be similar; yet even I noticed some increased responsiveness.
Previously, if I started to spin out, it was inevitable I'd crash into a lot of stuff.
Now I can reverse direction easily and repeatedly... so while I still crash into stuff, it's not guaranteed.

I've experienced a very noticeable change in the few vehicles I tried so far, but I haven't gotten used to it yet so it's hard to say whether I'd consider it an improvement or not. It's configurable in settings now at least so there is a way to affect how it works and tweak it more without addons although I haven't tried that yet. I've heard that tweaks for one vehcile may end up making another vehicle not work so nicely and that people want to see per-vehicle tweaks. In short it seems like it's a bit of a mixed bag for now.

I'ts an improvement for sure, the thing is, I'm not sure if it's better than "realistic driving experience" mod. For example the kusanagi keeps making this weird braking left to right movement, totally unrealistic, while with the mod, it was really pleasant to drive.

I guess I need to get used to it too and if not, I will put the mod back.