The Sulak case (there were actually three separate appeals in the case) is an unpublished decision which means that it cannot be cited as authority in California cases for any legal proposition.
You tend to see the MERS issue come up more in bankruptcy cases because the standard for “standing” to get relief from stay to foreclose is much more restrictive than when a non-judicial foreclosure takes place under California State law outside of bankruptcy.
I wouldn’t say the defenses that may arise in connection with MERS are useless in California. They are alive and well in bankruptcy cases, and may be available to a borrower in State Court to at least get a long postponement of foreclosure and negotiation leverage with the right set of facts. The borrower needs the wherewithal and resources to properly present them in order to obtain an injunction though. Its no slam dunk.