Perhaps not the popular opinion, but I'm hoping it's simply called "Metroid" or "Metroid Prime" and that it is a full on reboot and they completely reinvent it from the ground up. This is their chance to have a big FPS franchise, so whilst it needs to keep it's own identity, it also needs to learn some lessons from the biggest success stories in the genre. That certainly means multiplayer, as a minimum. It also means 2020 the earliest, in my opinion.
I don't see why the themes of isolation and exploration mean they can't have cutscenes and story telling... it could go down an "Alien" route and be very atmospheric and isolating. I don't think they should do that necessarily, but I do think they are throwing some big production budget behind it and will be seeking to captivate a broader audience. And that means some changes are needed, because as much as I truly love the franchise, it's batting well below what it could do. I believe Halo should be the ambition, and not a clone... at least in success terms.
If you want traditional Metroid, you've got the NES Online game. And if you want traditional Metroid Prime, you've got the Trilogy remake (hopefully!). Perfect time to bring something completely new to the table.