The root motion checks were actually mostly ripped out to save performance in some of the character movement modes, so even if the original mesh was in it wouldn’t be driving CMC locomotion currently.
I have a pathway to set the custom mesh being used so that the CMC knows which one to reference so a custom mesh could be used for such a thing if the code was in place.
I’m curious about why you intend to use root motion with VR though, considering its essentially direct control over camera movement most shouldn’t use it. I wouldn’t be entirely against putting the root motion code back in if there was a qualified reason for it. It would just have to be re-written to handle the offset capsule.
I’ve been back and forth over adding the default mesh back and re-parenting it as well. A lot of these were early decisions made a couple of years ago when first starting the character re-write.