Not that Zelda was really known for having super strong stories that are more than just "save the princess/kingdom from the big evil guy"

I kinda agree, because Zelda has always been gameplay-first, really, but I feel like (at least from LttP onward) most Zelda games had stories that were at least distinct from each other, if not exactly masterpieces. Like, Link's Awakening has the island thing plus Wind Fish. Ocarina has Ganondorf 1.0. Majora's Mask... is an experience. Wind Waker has its ocean aesthetic + sister, Tetra, and Cooler Ganondorf. TP has the Twili, Skyward is kind of its own thing entirely, and Link Between Worlds has Lorule. Pretty much all the Zelda games I can think of have an interesting twist on the basic plot structure... except TotK, which feels a bit like an amalgam of BotW and Ocarina on that front with some new items involved.

That's not to say it's bad - it works well for TotK, stylistically, and I think you're right on the mark in saying it was "whelming" - but I don't really think I want it to stay for future Zelda games, tbh. Though I don't really know how they'll merge a different plot style with open world, if they continue with the BotW style.