To be fair, the Yes campaign was not overtly Nationalist. But in that way it was misleeding and its non-Nationalist enthusiasts misguided, seemingly dismissing the existence of Scottish conservatives (there are lots of them, actually), or believing (or claiming) that the Scottish business class, or Scottish bankers, would be more ethical than the raptors of the City of London. It rested on the mistaken idea that independence would solve political problems, or would excise itself from an international financial system, class and culture. Or that, say, 10 or 15 years of SNP domination of a new state would not invite, eventually, a reaction, which could very well be neoliberal (this happens; it happened in Sweden, for example).
There is no reason why Scotland can't be a successful, independent nation, on the Northern European model, even if it did run out of oil (there would just be higher taxes, which might not be as popular). Whether that would be better for Scotland financially or in terms of defence is another argument altogther. The latter Yes position seems to rest on the idea of giving up a nuclear deterrent, which is a more esoteric and complex issue, although it comes down to politial preference at the populist level. There was also the NATO issue, dodged by the SNP.
Behind all of this, though, at core and stripping away temporal sympathies and assumptions, it is a Nationalist argument. It was an issue and a vote championed and triggered by the Scottish Nationalist Party. They may not have been pumping put Mel Gibson propaganda, but the basic attempt to argue that Scots are more socialist and ethical than, say, the inhabitants of South East England was a caricature and a judgement on two sets of geographically-determined populations that is not only disingenuous and false, but dangerous. The smaller you get, the more micro and vicious and ridiculous the arguments get. In an independent Wales (awful idea) the North and South would soon be squabbling (they have nothing in common), as would the urban centres and rural heartlands, as would (even more viciously) the Welsh and non-Welsh speakers.
I don't like the idea of Scottish independence because I abhor Nationalism, rather than conviction Pro-Unionism.
I will only concede that the argument is slightly different when you are talking about former Soviet states battling the political technologists exported by the Kremlin, or the small states ravaged and scarred by the Greater Serbia aggression of the '90s, or Kurdistan. I don't think that is to concede much, really, but I am sure most of you would disagree and call it hypocrisy.