As with just about everything else the voters in CA try to decide, it will run into the worst of federal scrutiny. There will be some judge that will agree to hear arguments after issuing an injunction. We will sit for YEARS while all the info is heard. In that time, the fed will be able to get their ducks in a row to effectively cease all federal monies coming into the state. CA is about as bankrupt as it can get and the legislature will cave.
It WILL force the issue though into the general population and so the discussion will become loud. It may bolster other states to follow suite and we will get the same sort of action that followed Prop 215. More states will begin to flex their "rights" muscle and eventually the fed will have to stop the 80 year war on Cannabis.
Just my thought on it. I believe that we will see it legal inside of 10 years, but WE THE PEOPLE will have to force the issue.