The proposal to split California into six states has gotten enough signatures to make the ballot. Assuming there are no irregularities with the signatures, this means it should be on the ballot for a vote in November.
I doubt the idea will get anywhere though, because it's one of those rare things that's bad for Republicans and for Democrat interest groups.
Splitting California is not in itself a bad idea. I suggested it back in 2008, drawing lines to make two states out of California, following the cultural contours of the state as it is today. We have an east/west split more than a north/south split these days, down more urban-rural lines. San Francisco vs Los Angeles just isn't as big of a deal as it used to be, with as many people coming to the state as we've seen over the last century.
Note that politically, the two-California plan leaves the Democrats where they are, but peels the Republican and some moderate parts of the state out. We could balance that, ensuring the Senators added are likely to split evenly, by breaking the coastal California in two. The plan to split California into six states goes much further than that.
The plan to be on the ballot creates three sure-Democrat states (North California, Silicon Valley, West California), a sure Republican state (Central California), and a states that could go either way (South California and Jefferson). I know it may seem strange to say that about Jefferson, but Jefferson is like most of the state in that it is split coastal/inland left/right. South California may have Orange County, but it's also got the whole Inland Empire which is going mushy moderate.
So as a result, we might predict this plan would take the current 2 D/0 R situation, and leave us with an 8-4 split, adding more Democrats than Republicans. Republicans would need to win both Senators from Central and one of South or Jefferson in order for the split not to favor Democrats.
That said, the unions might oppose this yet. Right now the government unions are in a great spot in the state. They control the the Democrats and therefore the government. They money flows in through forced unionization dues, they spend part of it to elect the people they want and they maintain what they have, then pocket the rest. Term limits and jungle primaries ensure principled politicians can't win or stay in office long, and turn elections into races to get the union bucks.
Why would the unions back a plan like this, which would diffuse the power they have, and in fact create some new states that might not be union-friendly, or even go right to work? It would not surprise me if the government unions oppose this plan, and so ensure it goes nowhere.
Ultimately, the problems with Six Californias are that it's not following the cultural contours of the state, it's too much of a partisan power grab, but at the same time it doesn't even respect the partisan power base the Democrats have in the state.
I expect it to fail.