I dont think the current wrong wheel tread separation has got anything to do with not running MRF. Wake characteristics of a rotating wheel in contact with a moving ground is closely related to the contact patch shape and the two main vortices, how the two main vortices alter the downwash, which reflects the tread separation. Or, if you look at the the other way, it is how the wheel rotation (mainly the tread surface rotation) alters the tread separation point, which in turn changes the downwash and therefore the two main vortices. We should and will get the tread separation right without MRF. Simply applying a rotating wall on the wheel can and will get the wake features.