Sooo....the MarioXRabbids rumour is alive again?....well yippee...
I'm not particularly a fan of leaks and rumours in general but with that said I wouldn't really mind some more hints at a possible Metroid title...
I think something's going on with Metroid since Reggie made a comment about "ask me again this time next year." Even if that didn't happen, Samus still showed up in a New 3DS advert a while back and has a couple of Switch user icons, so the IP clearly still carries some shred of weight in the company even if it's not exactly Animal Crossing level. I'd say a new title is inevitable, it skipped the 64 gen even harder than this one and that didn't kill it, and the 64 did a whole lot better than the Wii U did.
I mean, the IP is far from the most neglected of Nintendo's franchises, even in it's own general sales bracket. You're never going to see Metroid fall off the face of the earth for a quarter century under a healthy Nintendo.
That said, whether or not Retro's the one touching Metroid is a whole other matter. Their new project when they wrapped up Tropical Freeze apparently wasn't anything they worked on before (This came from the horse's mouth in an interview, I'm not just parroting old leaks. If anything you have to wonder what inspired those leaks. . .), so while them either canning it or working on multiple projects is definitely possible at the very least Metroid isn't a guarantee from them. I do think SOMEBODY's going to handle Metroid sooner or later, though.