I agree that a dynamic environment would be the best way to improve immersion, but I feel that the current interface between driver and sim is far too limited.
Suppose LFS could simulate a dynamic track: marbles, oil, weather, rubber buildup, etc. What good would it be if you can hardly see, hear, or feel what it does to the car? I expect most drivers would only spin out more often, and many spins would come unexpected because the driver never saw it coming. That would not increase immersion, it would raise irritation.
The average simracing rig consists of a decent FF wheel, a single 22" monitor and stereo sound. That's it. No force feedback system on the seat, because it's either affordable-but-botched or good-but-bloody-expensive. Pedals: ditto. Directional sound is not available in any sim, and most sims are sample-based. And a 3-monitor setup is considered top-notch, but is still far below the capabilities of your 2 retinas.
Until there are more ways to get feedback from the sim, I think I'll prefer a monotonously perfect track.