Relax for a minute. Yes, it did those things badly. But it did them. It doesn't matter if the environments were boring, linear corridors. It doesn't matter that powerups were so restricted and unrewarding to attain. It doesn't matter that all the music was basically monotonous white noise. The low quality of the game design doesn't change the fact that it did have a large space to explore that was full of powerups and obstacles that would require backtracking later on. It had a menacing atmosphere and a generally anxious tone. It executed all of this terribly, but technically, yes, on paper it is a Metroid game in its general concept- just realized in the most unfortunate and inept way possible.
Federation Force didn't even attempt to be a Metroid game. You didn't spend enough time in any of the missions to do the kind of exploration and backtracking the series is known for, discovering powerups to unlock new paths wasn't a thing, and the chibi/cartoony vibe was worlds away from what Metroid should be. So yes, Other M is much more of a Metroid game than FF. Why is this taboo to say? Do we all hate Other M so much that we have to take the most negative position on the game possible in every circumstance? I mean... I'm not even attempting to say anything about the game was good, but you'd think I had said it was the masterpiece of the series.
The fact that Other M would actually be a better game without any forced Metroid tropes is pretty damning.
Every single Metroid element in that game is an insulting attempt at pandering at the expense of the player.
As Metroid Fusion, Prime Hunters, Prime hunter 1st hunt and Pinball showed, it's ok if you try something different with Metroid as long as its competent.
People aren't mad at Other M because it doesn't tick the correct boxes, they don't like it because it doesn't do anything right but put surface element that people liked in other games in a sad attempt to try to make palatable elements that are woefully bad.
If FF manages to do its mission structure well and is fun enough, it doesn't NEED to be like usual Metroid game with backtracking and sprawling exploration.
It's a spinoff 1st and foremost, Luigi Mansion doesn't need Luigi to jump through the Mushroom Kingdom to make a successful game.
Yeah of course, Other M is more of a Metroid game.
In the same way that NSMB2 is more of a Mario game than Yoshi's Island.
And btw there's no 'new paths' per se in Other M, you're always railroaded for the entirety of the game.
No exploration, unless you think following Googlemaps is somehow exploring places.
(Heck the analogy is bad as you could choose to go elsewhere irl while you don't have that choice in Other M).
The extent of large spaces are mostly sectionned off setpieces with little to do and even less to look at.
The atmosphere is indeed anxious but for all the wrong reasons and certainly nothing intentional.
It is a Metroid game in the purest sense of the name: it has the name Metroid on it and it was done by Nintendo.
Everything else that the other Metroid games try to do is absent or mangled to the point of not being recognisable.
The fact that FF didn't even try to be anything but a spinoff is to its credit IMO.
Other M put surface element here and there, but everything else is going against what Metroid is and should be.
Even though on its own term it's still rather terrible, it's even worse when you take into account that it tries to fool the unsuspecting player into thinking he's playing a Metroid game.
I'll agree that Other M is more of a Metroid game but it's certainly not better at trying to be.