I already said it once and it's fresh on my mind, so I'll say it again.
Metroid Fusion is the worst 2D Metroid game besides the original. It's probably the most boring Metroid game to replay besides Hunters and Other M, because every five seconds Adam forces you to wait in a data room and skip his text, or Samus goes on one of those elevators and has a poorly-written inner monologue. The final boss fight is awful and is a ripoff of Super Metroid's with none of the storytelling that made the Mother Brain fight matter. The story reads like a Metroid fanfic, with Samus glorifying this new character we've never seen and coincidentally meeting the Zebes animals that escaped at the end of Super Metroid. There's a lot of tedious "go here and do this" plotting that makes you feel like Adam's janitor, a far cry from the explorer of other Metroid games. There are some really good boss fights (BOX, Nightmare, Yakuza, Serris), but the level design has none of the mystery and discovery Metroid 2, Super Metroid, and Zero Mission had, so you feel bored between said boss fights. The changes to the Morph Ball bombs and wall jumping felt like a "fuck you" to people who experimented with those abilities in Super Metroid. The Fusion Suit is cool-looking until you get the yellow upgrade, at which point you vomit at the horrible clown-suit.
*Deep breath*
I dunno, this might be a popular opinion, but I replayed Fusion recently and it really doesn't feel as good as the other 2D Metroids. And then I go online and everybody wants a sequel to this insipid storyline because apparently it's just sooooo interesting having Samus fight the Weyland-Yutani Corp-I mean, the Galactic Federation while having five minute conversations with her computer.
If we ever get another Metroid, I want it to be somewhere remote. I don't want it on a fucking space station or military base or whatever. Leave the Galactic Federation alone and explore the wilderness.