How about we make Other M a separate canon, and retell that part of the story correctly? It had all the ingredients for the Metroid game you want, just done wrong. Horribly wrong. But it really had the potential to be exactly what you're asking for. Perhaps a Re:Other M to right the wrongs of the original, and give the series something to build off of? I know many people want to forget Other M ever happened, and denounce everything about it, but it did have some merits. The setting and plot created the Alien feel, unnerving and eerie. It was 3D and 3rd person. If it had competent writing, less monologues, better character design and characterization of Samus, better level design so that Super Metroid levels of sequence breaking were possible without breaking the game (aka, no more Adam telling you that you can't go places just because he said so as a cop out excuse to not have to design around what the player might try), and better controls in general instead of forcing everyone to use the shitty, clumsy, cumbersome, uninspired, nunchukless Wiimote controls when better control options were readily available, it would be the game you're looking for. In other words, the basic premise of the game's story, telling the story of Adam and some of Samus' backstory, deserves to be done right, and behind all the problems, at the core of the game, was a 3D, 3rd person Metroid with an Alien like feeling to it, and hey, it had the speed booster and shine spark, and a much better screw attack than Prime did. It had a lot of potential, and deserves to be done right. As for the future of the series, plenty of games could be put between 1 and 2 if Nintendo really wanted or needed to.

Or a complete reboot of the series, that wouldn't be the end of the world. If Samus stays the mostly silent hardened badass that can singlehandedly blow up enemy stronghold planets and took shit from no one, the Samus we knew her as, a reboot would solve a lot of problems. Nintendo is too proud to reboot a story driven series though. Last time that happened was Star Fox 64. It's doubtable that they'd even consider it, though not unprecedented.

Didn't Nintendo say they won't be doing that right now since it's too similar to MK?

I don't ever want a Prime 4. The Prime series is definitely over. And it's not simply that the 2D Metroids were "fast paced." It's that they have such an intense focus on platforming that the Prime games simply can't accomplish.

Ew...

...Have you played a Metroid game that isn't Prime 3? That is the exact opposite of what the franchise is. If Nintendo wants something like Mass Effect, they need to make a new franchise, because that makes no sense in Metroid.

I would love for them to make a 2D Metroid on Wii U. Then, when you look down on the gamepad, you see 3D what is in front of you, like a helmet few.

If Nintendo does a Mass Effect style game, it should be with Star Fox. They're a team of mercenaries in a heavily populated system of planets with diverse cultures and races, yet we never see those people and the only ones that seem to hire this elite mercenary team is the central government, whenever system-wide war comes around. Let's fix that. Explore all the worlds to the depth that Adventures explored Dinosaur Planet, and let's see how the team makes money between wars. Have the Great Fox as a hub to go on ground and space based missions from. Some combat, some stealth, some reconnaissance. Metroid is just humans, space pirates, and a bunch of dead and dying races. Star Fox has MUCH more potential for a Mass Effect style game.

The entire premise of Samus being in the presence of other people is out of wack to me, so that is not the game I want at all. Other M exists to tell a story. That's its first and biggest flaw. Metroid isn't a game about telling a story; it's about discovering one. As soon as you design a Metroid who's purpose is to explain something, your premiss is flawed. Being restricted to a ship the whole time instead of exploring an alien planet isn't the way to go. I have absolutely no intrest in retelling the story of Adam because Adam should never have been introduced in the first place. That whole plotline just sounds like fanfiction.

I suggested that a good place to set a 3D Metroid is between 1+2. That's not because I care about what happens in that period; it's because the Metroids aren't extinct yet. They don't have to shoehorn in why the Metroids are still alive with some plot mcguffin. I have no problem with there being a deep plot in Metroid. I have a huge problem with someone making a Metroid game to tell a deep plot.

I don't want a Metroid game that's meant to flesh Samus' character out. The reason why Super Metroid's plot was so effective was because it could only be told through gameplay. No amount of scan logs could have possibly conveyed what it was like to see what happened to the Super Metroid. They used real gameplay elements to tell the story. Samus didn't need anything explained there. Seeing what happens to Crocomire would have had nothing added with a scan. You don't need exposition in Super Metroid to tell you that there are dead scientists and that the baby Metroid is out of it's container. You can see it. They are on the floor, unconcious, and bleeding. It didn't need a scan log explaining the details of how scientist B died from severe head trauma from being flung across the room. You can see that, clearly.

And I don't want an Alien story. I want an Alien atmosphere. Even though they have similarities that I want them to keep, they are two completely different franchises with major differences that I'd like to stay different. I think that audio logs can tell story through exploration, and I think boss battles can tell story through gameplay. I don't think that there is ever a reason to have a cutscene in a Metroid game either. The only reason Prime needed them was to show how cool Samus looks because you can't see her otherwise. They can just start with Samus picking up a bounty on a planet and ending with her collecting that bounty.

And Nintendo will never write out Other M. The fact that her suit design in Smash was changed to that of Other M proves it.

That would piss me off. The only thing that should ever be on the bottom of a 3DS Metroid game is a map.

No. Metroid is its own genre. Platforming roots perhaps, but that is all. Metroidvania is not just a subset of platformer.