That's true. But speaking for myself, I'm anticipating fewer characters this go-around, at least where the campaign is concerned, just because the scenarios will likely revolve around mostly pre-established characters. The ones BotW mentions as playing a key role (beyond those already confirmed) are Purah, Robbie and Rhoam. Those, plus maybe some villains (i.e. the Yiga leader). Dorephan would be awesome but he doesn't appear playable in the Zora's Domain scenario we've seen, though he could fight later.
Of course, anything is possible in a Free Mode or Adventure Mode. I would love to play as Sidon and Riju in a non-canon mode. I just get the impression they're heavily focused on the campaign and making it mechanically varied (i.e. unique slate powers for each character, etc).