I think E3 (or whatever equivalent) 2025/June Direct 2025 could be when the next Zelda is first shown. It matches up with BotW spring 2017 release -Tears summer 2019 reveal timeframe, and we’ll be a bit into the life of the Succ at that point, and probably post-3D Mario and Prime 4 as well, so they’ll probably want another big SP action-adventure title announced.
Animal Crossing really should be something they should try to squeak out in the launch window, same with Mario Kart. It’ll be years since each of those had full-blown console entries. Splatoon can probably chill for a bit while those two carry Nintendo’s online/GAAS games.
Speaking of that, the only thing I’m scared to even begin to predict is Smash, have absolutely no idea how they’ll handle that. Both in terms of what the game will be (Ultimate Deluxe or something brand new) and when it’ll release.