Forgive me if I've missed a point in the discussion but I'm still not understanding the grounds for these concerns. Ignoring the hypothetical future of British citizenship following independence (which is beyond the topic of this thread anyway), the current rules only allow for British citizenship to be transmitted to the first generation born outside the UK - so people who are already British citizens at the time of independence will be able to pass that to their children born in Scotland, but those children will not be able to pass it on any further. It's no different to how the children born to British parents anywhere else in the world today can inherit British citizenship from their parents, but cannot pass it on to their children. So given that entitlement to new British citizenship by virtue of connection to Scotland only will cease when Scotland ceases to be part of the UK, the pool of people who can claim British citizenship in Scotland becomes essentially finite.
Indeed the proposed Scottish rules are less restrictive then this, as (like the current Irish rules) they'll allow two generations of descent. The British rules instead provide only for the
UK Ancestry visa, which allows people with one or more grandparents born a British citizen in the UK (including Ireland before 31 March 1922) to live and work in the UK - though in fairness it can be used as a pathway to naturalisation.
The key point is that - by UK law as it currently stands - people who already hold British citizenship, regardless of how they're entitled to it, won't lose it as a result of Scottish independence, and thus won't lose their right of abode in the rest of the UK. Their Scottish citizenship, should they claim it, will be in addition to any they already hold.
I'm a bit bewildered by that too, if I'm honest. Even Australia managed virtually-complete metrication between 1971 and 1981 with no pressure from any international organisations and very little genuine bother.
Personally I'm ambivalent about monarchy. Retaining it wouldn't be my preference but I can see that doing so could be an important concession for people on the unionist side. And the
Royal Coat of Arms for a separate Kingdom of Scotland is really rather fancy (with double the number of unicorns!
)