To have any shot at legitimacy on par with, or better than, the Big XII, you would need more than just ASU, Arizona, Cal, & Stanford. The plan they are working on is just a slightly better MWC.
Drop Fresno and CSU, bring along the four already mentioned plus Colorado, Oklahoma State, Texas Tech, Baylor, and TCU. Now you’ve got something of worth and you kill your biggest western competitor in the Big XII. But those teams aren’t going to leave and neither is Utah.
Utah’s best option is to stay in the Big XII unless an invite to the B1G comes or the Pac-12 decides to get the band back together.