This is entertaining, but very very out of the question. A game developer like WayForward thrives on making a handful of smaller, lower budget games every year and would not have the time/resources to make a huge metroid-scale game, much less metroid itself.
Since Metroid is Nintendo's IP, Nintendo would fund the project. Therefore time and money wouldn't be an issue for WayForward, because Nintendo would cover these things. And in case WayForward needed more staff, Nintendo would be more than willing to have a few of their own people co-developing the game to ensure the desired quality of the final product.
The only question in all of this is if Nintendo is still interested in making a proper Metroid game. The same holds probably true for several other of their IPs, because there are definitely third party developers who would like to work on Nintendo properties (like Platinum Games who has shown interest in Star Fox).
How much do you think a Metroid game would have to sell in order to interest Nintendo? A million copies or so on the 3DS? Because Metroid has generally seen less and less sales over the years. The last two handheld Metroids couldn't even reach the million-mark. Admittedly, one was a remake and the other was an FPS, but that's still not encouraging.
I don't enjoy being a Negative Nancy. I really liked the non-Prime Hunters Metroid games I've played. I'm just skeptical of the series' future, especially after the Other M fiasco.
Metroid generally has a range of 1-3 million. Not great, but reliable