What I would absolutely love and they could leverage would be to mix both their new open-world and visual style with going back with the sea and island (and more cartoonish) elements of Wind Waker. I adored that game, where each island had its own flair, this could be expanded upon so much with the new engine.
I like the more metroivania style too of finding an element in a dungeon of island and then having it unlock more possibilities later elsewhere. I feel like giving all the powers and tools at the beginning of the newer games has put a damper on this side of the usual formula.