The Legend of Zelda: Breath of the Wild may have launched the Nintendo Switch to success, and may in fact be the system’s signature game, but funnily enough, it is not a Switch game at all- it was originally being developed for the Wii U, and made a Wii U/Switch multiplatform game at the last moment, much like what happened with Twilight Princess.
What this means is that Breath of the Wild, for as amazing as it is, is ultimately still a game that was made for the weaker Wii U (the Switch even in handheld mode is more powerful than the Wii U was, to say nothing of docked mode). We haven’t seen what the team could do once they set out to make a game exclusively for Nintendo’s shiny new console yet.
However, series producer Eiji Aonuma notes to T011 (translated by Nintendo Soup) that the next Zelda game could be made for the Switch, noting that the development team never got to pay attention to the full extent of the possibilities offered by the Switch, and that they would like to do that. This is actually something that he has suggested previously, before the game or the console even came out to begin with.
That said, he declined to share any more details on the game, or what it might be and when it might come out, beyond that.
One reason why this is notable news is that Zelda games famously take a very long time to release- the development cycle for Breath of the Wild was over five years. By suggesting that the next game could be on Switch, Aonuma has also implied that it might not be quite as far off as many would have feared.
It’s all speculation, of course- but no matter where the team goes with the game, I am sure we are all excited to see what they do after the seminal Breath of the Wild.