BOTW is my favorite game ever, it's crazy because until then my favorite game has always been Super Mario Sunshine, you know, my childhood game. Hard to beat your childhood nostalgia, but BOTW did it.
So I have high faith in EPD to deliver with this game, especially since they seem to go weird.
But here's some minor things I would love :
-Fishing rod. BOTW is a very calm, atmospheric game. Fishing with an actual fishing road is something that would be totally in tone with this environment. Also, some little boats, RDR2 style, that doesn't require the korok leaf.
-Underground was confirmed in the trailer, so it's cool. I hope it's massive, and totally interconnected.
-More horror also was confirmed. I had this feeling that it would be the Majora's Mask to BOTW (reuse of assets in order to deliver a sequel pretty quickly, so I hoped for more creepy stuff. Seems like it'll happen. More side quests like in Majora's Mask would be good.
-A big town. I'm not sure if the trailer is hinting at "still same Hyrule, but with different/new things" or at "we're going out of Hyrule", but wherever it is, I want a big town. Hyrule Castle Town in Twilight Princess was a big "holy shit !" moment for me. I would love if BOTW 2 was to recapture that moment.
Playable Zelda. If not in base game, I can definitely see them making her playable in DLC, as the big selling point. Anyway, Link could use the same tools as in BOTW + whatever his green magic arm will end letting him do, and Zelda could use magic. It would be awesome if, in order to get those magic powers, you would need to go to the 3 different magic sources, like she does in BOTW's story. Each one would give her a power.
-Unlike most of the people, I don't really want traditional, linear dungeons. This is so un-BOTW. Give me big, open dungeons, with multiple entrances. Hyrule Castle, but with more emphase on puzzles.