There's probably no one single game that would make me buy a console at launch. Well maybe FF7 Remake, and it's not even my favorite FF.
But I haven't bought a console at launch since PS2, and probably won't again. I have too many games still on my backlog to play.
As for Metroid, I'm more interested in a 2D version. But from the sound of it, they haven't begun development on new Metroid so I don't expect to see one at launch for NX.