Splitting California along the proposed lines would really be a bad idea. Northern California would be completely dominated by the Bay Area. What they want to call 'California' would be most of the Southern Coast and dominated by LA. If the more rural areas think they don't have a say now, imagine how bad it would be after the split?
Other than the coastal area, most of what would be called Southern California is extremely poor and generally a miserable place to live. San Diego would end up the most prosperous city in Southern California with the rest of the state a poor wasteland with very little income and short water resources.
Also, it would never get ratified because it would add four U.S. Senate seats, congress is already quietly ignoring Puerto Rico's request for statehood.