The delay on devolution was caused by the SNP insisting that it still receive the same or bigger subsidies from the rest of the UK, even though that struck many as unfair (part of independence is paying your own way). It's not like Parliament refused to hand over powers.
IIRC part of this argument was that Scotland contributed more than the uk average as well, they most per person outside London/South-East England. Additionally parliament haven't been particularly forthcoming over tax rights, easiest way around that argument was to split income tax into a federal and regional income tax and let us set the later.
