I understand how well he's hit, but he's apparently strictly a corner guy with the glove. Corner guys are supposed to mash. As a middle infielder (or, as of now, a CF or C), Frazier's bat profiles as plus. (Thus, his prospect wattage ascends.) But, as a corner, he's no more than average.
IMO, Valaika's SS/ 2B bat (and possibly Stubbs' CF bat) are more advantageous than Frazier's.