Hey thanks. I think you really hit the nail on the head with the unpredicatability... I have a build staged here which will go live on itch when rating ends and which does it's best to smooth out those rough turns.
I also think going procedural could be extremely powerful. And with some recent upgrades to the rail editor, I think this might be achievable in the near future.
If you are interested in doing any development for Rail Rider, please feel free to check out the github