I like those islands, and I think it would be interesting to play on a version that has mountains, or cliffs, or some height level differences, and more troublesome terrain. Maybe the outside of those islands would have a bigger difference in height, like if they were part of a volcano, and the center has a lower level difference because it was inside the volcano's mouth.

That way, we would have reasons to build blimps and cablecars, to get to the mountain peaks, for the people living there.