Weapon repair mechanics?
Take your broken weapons to a specialist in town, repair or ‘fairy upgrade’.
In the wild fix, carry some ‘forge’ items (wood, flint, forge hammer, + weapon material)
An actual recipe book, once you do certain food combinations, you can recall them via a menu, and you can automatically cook and adjust the recipe via the menu (if you’re at a cooking station).
A better way to sail would be nice too. Maybe introduce more items that can deliver more wind. Or simply have an upgrade system for the Korok leaf.
Maybe some animal crossing mechanics. Make friends in different areas, time based events.
Some farmville mechanics. Get better meats and cooking items with your own personal farm/ gardens