Nikolai II said:But core doesn't work, or else Gotland would be able to defect to Denmark and Cyprus (after revolter enddate) to the Ottomans.
I thought so too, until I actually saw Malta defect to the Knights yesterday in a game using the Feb 1st beta. It was not through the event. Maybe it was fixed.
IMO defections across water should be made possible, core or not core. Primarily to same cultured countries, secondarily to countries with the same religion as the rebelling province, if there are no adjacent countries to defect to.