Am I the only one who felt this looked like someone who had never seen or played Metroid, Skylanders, or Call of Duty was asked to make a game combining all three? Also, why? Did anyone else notice how it specifically referred to the Metroid Prime Universe, as if Prime weren't part of Metroid canon as a whole? Is this a real thing? Or am I reading too much into it?
I wouldn't be surprised if Prime is easily overlooked from a japanese perspective. The Prime Trilogy certainly is a completed sidestory that doesn't really have any bearing on the 2D games. They might be using Prime for all side games now. Also, Federation Troopers haven't really been around outside Prime.
As for this game, eh. They just wanted to make a co-op multiplayer shooter and decided to use the Metroid name for it. Doesn't really matter. Did they say anything about a singleplayer campaign? At this point it just seems like the next step from Metroid Prime Hunters. I certainly don't have any real hopes for a new Metroid anyway. Together with F-Zero, it feels like they still have love for these franchises, but they're not profitable enough to make a game for or they're just sitting on their plans while they take care of higher priority franchises. F-Zero stuff found its way into Mario Kart, can't really do anything with Metroid other than put Samus in Smash.
The design in this game is based off the Prime troopers. I don't remember if the Other M guys were just redesigned or some kind of special elite subforce. Wouldn't really say Fusion features them just because you see some for a second in a cutscene or something.