The jacket should be comfortable to move around in it in riding position and yet snug fitting, and should glide well , so no suede jacket or jacket with grabby details like tassle or pocket flaps, no lamb skin, any other spongey hide I can pick a chunk off if I try with my fingernails to begin with as a riding jacket.
in normal speed any jacket that match that criteria even when it's 5* (if spec'd with riding in mind) would perform equally I believe.
in high speed probably only several type of vanson that would save the rider against broken bones and spine if relying only on their jacket.
otherwise I believe there is nothing magical in the way they sew the panels that other makers don't know or can't do, by looking at this random no brand MC jacket surviving this abuse, I confidently say that
If I wear padded under armor or spine protector and elbow pad and wear just a goathide or any dense (non spongey) cowhide on top it might perform as well as long as the jacket fit well with those under armor on. the goathide would then need to be replaced probably and cowhide need to be repainted. and horsehide is overkill.
