From what I understand of the decision, I can't complain. Keep in mind New Jersey has an already existing statute which grants same-sex domestic partner benefits. This statute may grant many of the rights to same-sex couples that married couples have; but it doesn't grant everything. I read this decision as stating either grant marriage, or grant all of the rights, every one, so that the arrangement would be marriage in all but name only. And that's fine. Government need not be involved in granting the "name" marriage to any couple. But even if government does grant the name to heterosexual but not homosexual couples, as long as government grants same-sex couples every single right that married couples have, I think that's close enough to satisfy a meaningful concept of equality.
On originalist grounds, I see this decision as clearly growing out of the "seeds" of equality that the Declaration of Independence and founding principles first planted. It's certainly true that the Founders or the population at large didn't intend for this. However, when the populace at large heard that very broad and general phrase, "all men are created equal," arguably most people first thought: All white propertied Protestant males...a sentiment while which today would be unthinkable, was still remarkably egalitarian coming out of the throne and alter era of divine right of Kings and Aristocracy.
Like it or not, the twin pillars of classical liberalism -- liberty and equality -- have been consistently expanding since our nation was first founded in 1776, just as the Founders intended. As Jefferson put it:
"[L]aws and institutions must go hand in hand with the progress of the human mind. As that becomes more developed, more enlightened, as new discoveries are made, new truths disclosed, and manners and opinions change with the change of circumstances, institutions must advance also, and keep pace with the times. We might as well require a man to wear still the same coat which fitted him when a boy, as civilized society to remain ever under the regimen of their barbarous ancestors."
Now, one can argue that they didn't intend Constitutional rights to so evolve, that the evolving should be done via statutes and the common law. But liberal democracy is predicated on the notion that individual rights -- liberty and equality rights -- exist prior to majority rule. So it makes sense that a countermajoritarian institution like the courts would get the final say on individual rights. And, given that we inherited a common law system where judges entirely created substantive norms (damn important ones like contract, property and tort) in an evolving body of law, it makes sense that judges today (as they historically have) often play very prominent roles in substantive rule making and rights recognition.
My biggest concern with gay marriage or its equivalent by judicial decree, on originalist and separation of powers grounds, is that while judicial nullification clearly exists within the original meaning of the "judicial power," something else may be going on here. Judicial nullification is not the same as when judges exercise a quasi command and control power ordering other branches of government to take affirmative action. When judges simply strike down laws in the name of liberty and do nothing else, they are acting entirely consistent with the way our Constitutional Republic was originally structured. However, when judges exercise a command and control like power, as they often do in the name of equality, such may not be as defensible on originalist grounds. (I could be wrong; if someone wants to point me to the scholarship, I'd greatly appreciate it). Nullifying a statute or act of government on equality grounds also would be consistent with the original meaning of the judicial power, as well as the very powerful notion of substantive equality under the law, which is foundational to liberal democracy.
Whether gay marriage will come to the US universally in every state, and how it will finally occur, I can't entirely answer. I hope we get there and think we eventually will. Right now, the gradual state-by-state approach seems the most judicious.
A Supreme Court decision finally resolving the issue? In my opinion, it would be wisest for such a decision to occur after a vast majority of states have already recognized gay marriage. So far, we have at least one, perhaps two out of fifty. We are a long way away from gay marriage at the national level, in my opinion.