What makes you say Scotland would have been worse off independent? In the 1970s the UK government commissioned a report that concluded Scotland would be a very wealthy independent country. The report was kept secret. In the meantime Norway did become a very wealthy country, while UK revenue from the North Sea was used to fund 1980s privatisation and tax cuts, and none put aside for the future. The UK also spent a fortune on wars and weapons of mass destruction. How has any of that improved Scotland's position? Scotland has been a net contributor to the UK for most of the last 40 years. Only in the last couple of years has this reversed slightly. The Independent - hardly an snp paper.
Given that history how on earth can you say Scotland has been better off in the UK?
The table at the bottom of this page shows that Scotland raised slightly less revenue per person than the rest of the UK for the last two years, compared with years when revenue from Scotland was much higher than the rest of the UK.
http://www.bbc.co.uk/news/uk-scotland-37167975
There is no doubt that the last two years have been tough for Scotland because of the low price of oil. But that's within the context of years and decades of net contribution to the UK. And if Scotland was independent it could have put money aside as Norway did. If Scotland is independent in the future it can make better decisions about its economy than the UK has made.
It's as if unionists think staying in the UK actually constitutes an economic plan. Scotland needs to adapt whether it is independent or not. The Barnett formula won't last forever whether we are independent or not. Or is it really the plan to rely on subsidy from now on indefinitely? Good luck with that economic plan.