Whatever the prospects for American on a route from JFK to Europe, the prospects for Continental on the same route from EWR will generally be better because Continental has far more ability to back up its routes with connecting traffic.
So, assuming that Continental is pleased with its 757 trans Atlantic strategy (and it seems to be, since it's still announcing new cities, the last being Cologne at the end of October), it's certain it will give NCL careful consideration.
What's the economy like in the Newcastle area? How easy is it to scoot up to Edinburgh?