You're right, because the possibilities could be endless if Sakamoto, Tanabe and their respective teams truly worked together, taking turns at telling various episodes in the overall Metroid saga. But it is what it is.
Again, all the more reason I advocate for a true split.
I definitely wouldn't go that far, but more to littler benefits, where different elements can intentionally complement or contrast each other, or little bits of worldbuilding can persist, or touches of character can build. Basically, where the aforementioned Kriken can be referenced as a concern of the Federation, rather than throwing space pirates back into it. Or where we don't bring back and kill Ridley again lest it appear ridiculous. Or where the structure of the Galactic Federation is coherent.
Come to type it out, it's not even all a concern of communication, but rather a willingness to take elements into consideration, just the slightest touch of coordination.
I'm sure I've mentioned this before, but I don't think the different lines of
Metroid need to be terribly interconnected in general. They can have their own stories to tell, rather than only telling one, and that can help the universe feel just a tad less constructed. The earlier suggestion would essentially be its own story, after all, just playing with pieces that already exist from elsewhere; however, it does seem it might rely a bit heavily on the larger story in order to itself be narratively fulfilling.
And I'm not sure you really gain much from a true split, at least unless one line goes off the rails. Different subseries can coexist in one continuity, even if they never actually interact. There's room to have different things happen that aren't always directly connected to something else.
Eh, I very much prefer the two series to stay separate. The longer each go on the less sense both make together. I’m of the idea that the Prime series starts with the original Metroid 1 and that the 2D series starts with Zero Mission. The two series have never come together to tell even one plot beat together. Even Proteus Ridley in SR just seemed to me to be the 2D series way of explaining his ass whooping in ZM. I love both series and would prefer they do their own thing.
I mean, I'm also on record as thinking
Prime has probably reached a narrative completion and the next thing should be separate, which kind of takes care of the concern of it running longer. But I'm also in favor of also trying third-person 3D again, which would also be its own thing.
But I don't think they need to be considered different continuities. There should be enough room for different storylines to occur throughout the timeline, so long as care and consideration is taken in their construction. They don't need to directly connect in order to exist in the same universe. But maybe eventually there'll be something. For the most part,
Metroid hasn't told plots where I'd necessarily expect the different subseries to come together to tell a plot beat anyway.
For Proteus Ridley, yeah, I very much doubt it's meant to be connected to
Prime at all; it's merely a happy coincidence
-- though I would have been perfectly fine just not bringing him back for that encounter, but it is what it is. Though intended connections like that could be, if well-considered, a benefit should the teams work together just a bit more, but for the most part the specific connections probably aren't and shouldn't be necessary.
But this is actually the strongest point against the specific concept I'd thrown together, I think: it's likely to be unfulfilling on its own.
Ehhhhhhhh, as someone who literally got an epileptic seizure playing Metroid Prime. I'd really rather not have something make it required I play the Prime games to understand the plot.
And honestly, the plot not mattering until it does is standard for Sci-Fi pulp which Samus is clearly emulating. I don't want to end up in this comic book lore where I have to know what happens in a series I'm not interested in so I can understand what's going on in another. And yes, I consider Prime its own series because I physically cannot play nor want to risk my own life playing a video game, no matter how many awards it gets.
Metroid is generally pretty plot-light, yeah, and I'm pretty sure I'm on record here suggesting that it doesn't need to be made consistently more plot-heavy and that it's perfectly fine for different subseries to not be intertwined. Even the post above suggests the different narrative lines exist mostly in the background.
Beyond that, the thing with something like the thrown-together example earlier is that neither current line is technically required to understand it. The Kriken, for instance, are involved through one character in a spinoff and would have to be properly introduced, so far removed from any plot that's been introduced that this is itself separate. And the X is really just a generic destructive space virus, where all necessary information should be able to be introduced along with it. It should be understandable all on its own; the structure, though, probably leaves the X bit somewhat unfulfilling.
To go further, I actually think the Kriken might be difficult to properly integrate into
Metroid proper (and were really only here because I wanted an actual threat that's not space pirates), though one title with them could theoretically work. Again, they're basically a non-entity as-is, and nobody's losing anything for having not played something else. And the X could just as easily be some other existentially horrifying life form in the harsh void.
Which reminds me ...
I've started playing DMantra's highly regarded Super Metroid ROM hack, V I T A L I T Y. This is among the most popular SM hacks, and I'm glad I've finally gotten around to it. It's been a highly immersive experience so far, featuring darker aesthetics and tone relative to vanilla SM, and seemingly taking heavier inspiration from Alien and H.R. Giger. I'll report back with more detailed impressions after I finish it.
I've thought for a while that a
Metroid game could probably do well to lean more into that vibe and aesthetic. Use that as a basis, iterate and twist it for various areas, perhaps add in some Beksinski vibes in some areas. Enemies can get the same treatment.
Give Samus the particular sort of organic metroid-based exoskeleton suit I've had in mind since
Fusion, and she could even feel eerily in-place within the setting.
It seems fitting, really.
Also, just because I explain something thoroughly doesn't mean I'm upset or arguing, so I hope it didn't come off that way, just to be clear.
It's unfortunate that it often seems to get interpreted as such. I probably like my tag too much to actually do it, but sometimes it seems it might be a good idea to change the text to "I'm probably less emotionally invested in this conversation than you are" or something, but that probably comes across as a bit aggressive.