Hi uh, here’s my thought after watching a twenty-minute long video. If you look at the pictures in the trailer carefully and find the same spot in Bot, you’ll see that the bokoblin horns are longer, however, the most interesting thing is that all sheik towers disappeared, and there are no lava on the death mountain. So I think it’s a time before the Sheikah towers and that’s 10000 years ago (?) Back in BotW there’s a kid in the forest stable. She says that people once lived in the sky in the ancient times... What’s more, if you go to Impa’s house and listen to the ancient legend again, you’ll see that Link in the trailer looks really similar to the ancient knight, especially the green patterns on Link’s right arm. In the previous trailers, there’s a green hand underground and a lot of players think that the hand is from a kind of power of Sheikah, but I think it’s at least related to the Zonai tribe, and according to the story Impa told, the hand is likely to be the ancient knight’s. Because of the hand, Link seemed to get new powers (similar to the Sheikah runes), also when he use some kind of Stasis power, Link didn’t use the slate at all. So my guess is that Link and Zelda went back to the ancient times and tried to stop Ganon (or Ganondorf) completely and I hope the Zonai tribe’s disappearance in BotW will get explained
(Some theories credit to Zeltik on youtube and Zelda with short hair on bilibili)