Imo Star Rider is far more impressive than GP World. GP World doesn't have any of the screen panning functionality that Star Rider does, and the 2D sprites don't blend well with the live action video at all.
For me, the top 3 most advanced LD games are Cube Quest, Star Rider, and Freedom Fighter (which one version uses similar hardware to Star Rider but doesn't use any Manchester data and basically combines the tech of Firefox's instant video switching and Star Rider's screen panning).
I'd guess the reason why Star Rider uses Manchester data encoded in the LD video instead of putting that information into the ROMs was space reasons?