So, Ocarina of Time in a BotW open world?
Much more like "hyrule is at war" than ocarina. Like for example a "dungeon" could be the goron village is captured and you have to get in and take out ganon's forces occupying it. Maybe another area is under siege and you have to go through the enemy encampment and take them out to free the area, and you could do that a multitude of different ways. Maybe another one there is a hyrulian force imprisoned and you have to free them and then fight your way out with them in a series of battles. Stuff like that. Where each dungeon has different objectives and you are free to figure out how you want to beat the dungeon, no one specific way presented. And shrines could be like taking out mini defense posts scattering around the world. Maybe each defense post shrine you free some soldiers. With hyrule castle being the final target but its defenses are such that you can't possibly hope to engage them until you've freed a bunch hyrulian forces and perhaps gained some key powers/items from the dungeons. Then once you have enough forces together you can decide to engage in open battle with ganon's forces outside hyrule castle, if you break through then you can get into the castle and work through that final level. Or maybe there are multiple ways to attack hyrule castle and you can come up with different strategies. But the whole world is open BotW style while still having a story line that makes it so you need to complete some dungeons and shrines first before you are strong enough to take on the final area. Something along those lines.