I actually think that a lot of good could come from splitting up California. This would allow the intense stupidity of its politics to be less monolithic, and would permit more experimentation with policy, which might have a good outcome.
That said, as a former San Luis Obispan, the notion of being an adjunct of Los Angeles (see http://www.sixcalifornias.info/) makes me shudder. And having Los Angeles and Orange County in separate states makes no sense. If you were going to carve up California along lines of economic and cultural interest, then I'd adjust the Six Californias as follows:
Jefferson (blue, in the far north) -- looks about right (and has a great history, worth reading about).
Northern California -- I'd swap Alpine, Mono, and Inyo counties into this state (from Central Valley), as this creates a state which is dominated by wilderness, tourism, and natural resources.
Central Valley (red) -- I'd take San Benito from Silicon Valley, to create a state which is unified by agriculture.
Silicon Valley (yellow) -- I'd shift San Benito to Central Valley and Monterrey to Central Coast (green), creating a more technology-centric state.
Central Coast (green) -- take Monterrey, but send Ventura and Los Angeles to Southern California. This is a rural area dominated by nature and tourism, and shouldn't be swallowed by Los Angeles politics.
Southern California (orange) -- take Ventura and Los Angeles from Central Coast, so as not to split up the overall conurbation.
Chances of this (or any version thereof) actually happening? Nil -- but it's kind of fun to think about.