The one area Breath of the Wild really stumbles is when it comes to dungeons. Gone are the longer dungeons, making up for the lack of sprawling labyrinths with the multitude of smaller Shrines all over the place. The Divine Beasts are creative but too short, and the change they offer in gameplay style is over too quickly.
However, assuming Breath of the Wild 2 is a direct sequel that doesn't take place after some multi-thousand year gap, there's not much reason to revisit or re-use Shrines, nor can the Beasts make a return. They've all been explored; they've all served their purpose.
It's always possible Nintendo will give us new Shrines that exist for story reasons, but the general consensus is that the series needs its dungeons back. They'd be better than Shrines too.
True, BotW shook the formula up by using non-mandatory mini-dungeons, but there's no reason dropping a handful — not necessarily 8, maybe more, maybe fewer — of dungeons in the massive open world would detract from that sense of freshness. In fact, it'd be an excellent contrast to that open world and expand the promise the Divine Beasts left hanging, since they'd require a longer break from exploration and put players' skills to the test.
That could be done with some traditional gear-based puzzles or even with just the Runes. The few Runes Link wields in BotW are brilliant in their simplicity, and even after 100+ puzzles in the Shrines based on them, there's still so much possibility for further use. Much as I'd like to see some key story items return, I'd be perfectly happy with some major — and completely breakable — puzzles built around expert Rune use.
They don't even have to be "dungeons" in the usual sense. Breath of the Wild's Hyrule Castle is an excellent example of a non-traditional dungeon; just add more traps and puzzles, and there you go.