Yup, considering the rise of Fracking and other techniques, the price of North Sea Hydrocarbons may not be quite as stable as first thought, especially considering there are plans for an Oil Fund based on that resource as well. It can either be spent or be saved, but if the price fluctuates too much, it cannot be both.
I suppose in summary, I would say that Scotland as a country would benefit from more autonomy (though not necessarily full Independence), however, I'm a long way from convinced the SNP, with their own axe to grind with Westminster, are really the best people to be organizing the terms for that autonomy, it's getting more and more about vendettas on both sides than about Scotland and England as modern societies.