Just seeing the dungeon maps laid out like that takes me back, dude. Such detail and consistency and awareness of each neighboring room or area. That's why I think games like ALTTP, OOT, and MM felt like massive, lived in worlds, despite the "overworld," consisting of like...areas a quarter as large as the Great Ocean at it's largest points. I used to think it was primarily applicable to the fact that open world wasn't a genre back then, so anything organized in a grander way than "Level 1 - Level 2 - Level 3," seem alive, but now I'm thinking it's a bit of column A and B.
A big portion IMO of what has made Zelda what it is has always been the Dungeons and Dungeon design all the way back to Zelda NES. You are thrown into a world that has these old ruins that you explore and acquire items that aid in your progression towards becoming a hero and usually defeating the big bad guy. While simplistic at first things got more complex.
Games like Link to the Past and Super Metroid were loved for this and the impeccable level design in games like OoT/MM/TP/WW, OG Tomb Raider, Golden Sun among others were and sometimes still are top tier both in design but also in atmosphere. Dragon's Dogma 1 kind of has this too in it's select dungeon like zones.
And for MMOs you easily have Everquest and Final Fantasy XI. Man dungeons in Vana'diel are so good. Just yes.
But it's also traversing that world and getting to those dungeons. I think Zelda Fallout Edition can achieve this but they really got to make dungeons with level design akin to the classics. The sandbox structure is fine but add meaningful exploration to it. You have to make a world with stuff you want in it. You don't make a map and then decide what to do with it. Or make a map and have 100+ shrines that instance you to another room you load into...completely disconnecting you from the world you took the time to create.
I also think the game cheapens itself by essentially giving a majority of your gear to you through shops or just stuff you pick up. Or for endgame stuff...farm Dragons for materials to upgrade gear. No real associated quest. Mind you there are quests for this sort of thing to get some base gear regarding the dragons in BotW...but in TotK not really.
Because a lot of my time with TotK I really enjoyed traveling to or making the "dungeons" accessible(Lightning Temple triangulation beacons was cool stuff) but when it comes to doing them it falls flat on it's face. Especially with the options available to you. They really messed up with how much you trivialize things with Rocket Shield or Ultrahand.
Right now for that proper dungeon experience given Zelda Fallout's MASSIVE SALES I can only really see them continuing with the current formula or altering it slightly.
For that classic Zelda experience for new games you will be relying on Indie Devs to provide. Crosscode and Unsighted as great examples. And Alabaster Dawn and Abyss X Zero look promising in that regard as well.
For the big studios I only really see Metroid Prime 4 being the kind of traditional Zelda that old Zelda fans are looking for.
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Last thing. Regarding optional content. To me the side quests in older games were meaningful, contributed to lore or rewarded you with upgrades or a unique item or piece of gear and was always worth doing and never felt like a chore. In newer games...there is plenty of activities to do....but you either don't want to do them or the rewards for investment are so insignificant they aren't worth the hassle. Now I don't know about you but a quest chain to acquire a sword is always more interesting then collecting 500 poops for 1 megapoop.