The current tyre physics uses a slip-v-force curve that is made up to resemble the real thing, but not really based on physical principles. The lateral and longitudinal forces are combined in a made up way to produce reasonable results but again this is not based on physicsl principles.
So the result is that in various ways, the current LFS tyres don't react just like the real thing. We did make a lot of comparisons with real test data to try and get good results all those years ago and that's why it is not bad to drive.
I don't want to start discussing the new tyre model at this point but it is based on physical models of real tyres (with some assumptions and approximations) and compared with experimental data in better ways. The model is separated into the tread (contact patch) and the carcass (the belted, inflated, deformable structure).
My plan at the moment is to get the new tyre physics to a good condition where we are happy that it works better than the old one in all situations and then release it. There will always be more to be done, as it's not possible to make a perfect tyre model, so I expect there will be more improvements to come later, but without needing a complete rewrite.