Mario AND Zelda both being at launch would be incredible, but I have to agree that it'll probably be one or the other, as that's just better business. Especially if the Splatoon port or even the Mario Kart 8 port are at launch, too. Makes more sense to space them out each month or so. And I always assumed if Zelda was at launch, Mario would be a holiday title, but if Zelda is 'delayed' to June (which would hopefully be the latest), then I can see Mario at launch to make up for it. And then hopefully they have some other big games ready to reveal at E3 for holiday, like Retro's next game, or Animal Crossing, or yeah, Pokemon Stars even would be a big deal.
Upcoming Games To Get
Definite: Kirby Star Allies (Switch), Mario Tennis Aces (Switch), Fire Emblem (Switch), Yoshi (Switch), Pokemon (Switch), Kingdom Hearts 3 (PS4), Monster Hunter World (PS4)
Considering: Fe (Switch), Donkey Kong Country Tropical Freeze (Switch), The World Ends With You (Switch), Ys VIII (Switch), Street Fighter V: Arcade Edition (PS4), Kingdom Hearts 2.8 Remix (PS4), The Last Guardian (PS4), Shadow of the Colossus HD (PS4), Anthem (PS4), Shenmue 3 (PS4), WiLD (PS4)