I have one word for you on this: Water. Putting aside the issues of breaking up the university system, infrastructure maintenance, prisons, bond debt, et. al. - the fight over water would be insane. I can't imagine how that would play out in reality. I am pretty sure it would be very difficult and ugly. LAT has an overview piece here.
Just to give some perspective - let's say a multi-state authority - think along the lines of New York/New Jersey Port Authority - was established to manage water between the three states. The Port Authority of NY and NJ has jurisdiction over the Hudson River crossings, the three major airports in the region - JFK, LaGuardia, Newark, and other multi-state infrastructure (e.g., Bayonne Bridge). In practice, this isn't always such a great idea - we lived in NJ and watched NY and NJ try to jockey resources of the PA for its own benefit. An example of this was Chris Christie redirecting PA funds for repairs to the Pulaski Skyway in NJ - an old freeway entirely based in NJ, that is not a Hudson River crossing that would fall within the scope of the PA. Additionally, both the NYC and NJ governers (Andrew Cuomo and Chris Christie) also vetoed legislation that was unanimously passed by both state legislatures designed to provide more oversight to the PA - in part because of the Pulaski Skyway issue.
California is a diverse state that for all its faults, manages to lead the nation in technology, environment, the economy, civil rights and countless other issues. Yes, we have major problems as well - lack of public school funding and an acute homeless crisis are two - and yet we still manage to have influence both in the U.S. and around the world. As the fifth largest economy in the world, California is a force to be reckoned with. I see no reason to walk away from California as the strong, united beacon it is today.