How California currently works is there are 3 levels. The EMT-1 (EMT-B), EMT-2 (EMT-intermediate, rare), and EMT-P. For the EMT-1 and EMT-2 levels, there are several "optional skill packages" that the counties can adopt. So if an EMT-1 goes through, say, the medication package in SD, I believe that he should be able to be signed off on the package without a new class if he moves to another county that
uses that package. For example, if the EMT-B with the package moved to Orange or Los Angeles counties, then he wouldn't be able to provide those interventions since those areas don't use that package.
I just went through the changes listed on the link. From what it looks like (I'm admitedly not that familiar with the scope of EMT-2s in California since they are extremely rare), the EMT-2 is somewhere between the current EMT-I/85 and EMT-I/99. Essentially the changes being made are bringing the EMT-2 down to the standardized AEMT level with the certification exam being moved to the NREMT in July 2013. From what I've read earlier, there may be a few interventions that the AEMT can provide that the current EMT-2s can't and they aren't looking at including those interventions at this time.
Based on the fact that AEMTs are still going to be considered a "limited advanced life support (LALS)" provider and an impact study has to be done if an agency wants to decrease service from ALS to LALS. As such, I highly doubt that the changes are going to mean much since most urban areas probably aren't going to accredited AEMT providers, even if it is a little easier now per statute. What I can possible see happening is some services looking at this as an EMT+ than a limited paramedic.
On an interesting side note, current EMT-2s in California will be able to keep their current scope of practice if the county allows them to work as one. So there's the possibility of California having a 4 tiered system, EMT, AEMT, grandfathered EMT-2s, and paramedics. If EMT-2s weren't limited to very rural areas (there are an entire 2 schools that produce EMT-2s in the entire state), then this could be confusing. However it is essentially a non-issue.
Edit:
Going through the EMT-B changes, a lot of the changes here appear to be more house keeping than anything else, especially with standardizing terms (good bye EMT-1 and EMT-2 terms). That said, they are getting rid of the stupid supervised manual defibrillation optional skill. It also looks like the state is getting rid of the medication package currently used in San Diego.
http://www.emsa.ca.gov/about/files/EMT2010/Ch2EMTRegsApprovedByEMSComm.pdf Bottom of page 17 to bottom of page 19.
Edit 2: It looks like California is also introducing a central registry for EMS providers
http://www.emsa.ca.gov/about/files/EMT2010/Ch10CentralRegisryApprovedByEMSComm.pdf