My take is that unless the concept of the section championships is done away with there cannot be a state playoff. All the teams reach a point and then its a judgement call like it is today.
In order to have a 5 week playoff with the 5th week being the state championship that would limit the teams in the playoffs to 16 for each level. And that would be the best 16 from all of NorCal. So if you had Open, D1, D2, D3, D4, D5, D6, that would be the "best" 112 teams in the "NorCal" which would be the CCS, NCS, Northern, SJS, Oakland, and San Francisco (and maybe Central) in the playoffs. 16 to 8, 8 to 4, 4 to 2, 2 to 1, and then 1's from NorCal vs. SoCal in week 5. It would be even harder in the SoCal region, they are a lot larger than NorCal. Maybe they go an extra week and start with 32 teams in each bracket. That would also mean that there would likely have to be a realignment under a SoCal & NorCal 'region' to which the sections would report. That would be the organizational body that would do the playoff seeding.
One option would be to take all of the league champions into the playoffs, then seed the rest by rating and factor in size. Draw the line and that's the playoffs.
It also means that the best teams would play each other and they would knock each other out of the playoffs. And no dropping down and playing in the lower division. So if Folsom and DLS meet in round 2 or 3 of the Open, one of them is not representing NorCal. Given that, what is the incentive to get into the Open division?
If you take only the top 16 teams from NorCal/SoCal, you would take all of the league champs, but after that 6-4, maybe 7-3 is no guarantee you will get in. You could be 9-1 and not a league champion and not get in because of SOS or something.
If you still want to have section champions then those are 3-week playoffs, 8 teams get in at each level in each section and get a champion. Then draw lots to see which teams would play in the NorCal championships (week 4), and then those winners go to the state championships. Or, if you're worried about the game just being for gate receipts just pick the teams without that 4th game. That leaves a lot of section champions outside looking in.