I'm not an SNP Kremlinologist, so I can only guess at the significance of the deferral of a decision on legislating for same-sex marriage. However, given that we now know for sure that there will be a verdict by the end of July (ie. in less than two weeks), it seems overwhelmingly likely that we are still heading towards marriage equality, and that all the cries of betrayal and foot-dragging will look pretty silly in short order. I certainly hope so.
The fact that there isn't going to be a referendum on the subject is scarcely a surprise, but it was still a good idea to slap down Cardinal O'Brien's demand so firmly. However, I do think the Equality Network's widely-reported suggestion that a referendum would be "un-Scottish, unfair and a colossal waste of taxpayer's money" was slightly misjudged. The term 'un-Scottish' has a fairly obvious McCarthyite ring to it, while any recourse to the notion that a democratic vote is a waste of money is pretty much always disingenuous. The No to AV campaign, for instance, notoriously lumped in the cost of the referendum itself as part of the supposed "price of AV"!
In truth, there's a perfectly respectable theoretical case for having a referendum on this sort of topic. Of course, in an ideal liberal democratic world, we'd accept that equal rights for citizens (including marriage rights) are sacred, and should not be subject to a veto by majority vote. But we don't yet live in that ideal liberal democracy, and for as long as individual freedoms are at the mercy of a majority vote, it's no more irrational that the vote should be conducted among the population at large than among their elected representatives in parliament.
No, the question is instead one of consistency. There is simply no precedent in this country for a referendum on anything other than matters relating to the constitution, or changing the form of government. The only possible example I can think of is the 1994 Strathclyde water referendum - but that had no official standing, and in any case was 'constitutionally motivated', ie. it was intended to show that a Conservative government in Westminster had no mandate to act in Scotland.
It would be different if we lived in Switzerland, or even Ireland, which has held referenda on very similar 'social' matters such as abortion and divorce. But while there's much to be said for Swiss-style semi-direct democracy, in my view there's even more to be said against it. The fact that Switzerland didn't allow women to vote until 1971 (entirely as a result of the referendum system) tells you all you need to know. So the tradition we're developing in this country probably has the balance just about right - while referenda are not necessarily a bad thing, they should be strictly limited to vital constitutional matters.
Which brings me to my second point - that NATO membership is just such a vital constitutional matter, and that proposing a referendum on it would not only be justified, but would neatly solve the SNP's dilemma on the subject. I personally don't see the need for the change in policy on NATO - even if it's true that an anti-NATO stance is scaring the horses somewhat, the obvious antidote is to point out that it's simply one political party's stance, and that the people will choose whether Scotland remains in the alliance at the first post-independence election. However, there's an argument that the electorate are bound to wrongly equate SNP policy with "what will automatically happen under independence", in which case a referendum pledge is surely the way to square the circle. A straightforward flip from an anti-NATO to a pro-NATO stance is simply going to dismay and demotivate as many voters as it reassures.