I was thinking something alongside that idea as well. But instead I was thinking of Settlers can embark at sailing but other units could if they would be in formation with them, in order to populate islands quickly. And maybe something about reefs maybe adding to appeal of adjacent land tiles and seaside resorts gaining more tourism. Now that Scotland on it's own, it looks like the Celts are going to be de-blobbed, so I think Polynesia would as well. In this instance I think it would be best to put this into a UA though of a particular culture although I'm not sure which one it would go to. Samoa would be my preference out of all the Polynesians but I wouldn't be picky if it would be easier to go to a different group, although I think this would still suit them.