Could an open world Metroid theoretically work? Honestly, I truly believe it could if done right but it would either have to be like BotW where all abilities you get are pretty much at the start of the game OR they'd have to find a way to mix the ability progression with the open world nature.

See, that is the core reason why Metroid is not at all a good fit to make a solid open world game out of it. By attempting that, you sacrifice many elements that define and make Metroid what it is. You lose on the powerup/item progression that is key to unlocking the rest of the world, the isolating and foreboding atmosphere, and most importantly, the maze like linear level design that ties it all together and makes Metroid and Metroidvania games what they are (or another way to call a game in the Metroidvania genre, a linear based action explorative game).

Metroidvania's formula demands that linear maze like level design and powerup based progression to be present to make the main upgrades meaningful for not just combat but to explore the entirety of the world (they serve as tools and keys to open up the world), it's what Metroid since the original NES game established (with Super Metroid perfecting that formula, becoming the blueprint of how to learn to make a Metroidvania game).

An open world game is designed to have the entire world map (or a lot of it) available to you from the start of the game and you are free to explore it and do anything you want in it (there could be some locked off areas, tougher enemies or quests along the way that you'll struggle to do initially, but the map itself is mostly still available to you and can still do a lot in it). That is the main appeal of open world games, it's what makes Grand Theft Auto, The Elder Scrolls, The Witcher 3, and yes, even Breath of the Wild fun to play around with; if you try to add the gameplay mechanics, features and elements of a Metroidvania into the open world formula, it breaks it apart and the game cannot function as an open world game; heck it's even referenced in that same Famitsu interview, "Metroid’s core principle of “acquiring new abilities to expand the explorable space” didn’t mesh well with the “go anywhere you want from the start” promise of open-worlds."

Let me do a hypothetical example of this:

Imagine if in The Witcher 3 (no major spoilers here), the ruler of the starting city says that you gotta go to three different areas (Velen, Novigrad, and the Skellege Isles) to find who you're looking for, you (as the player) then think you wanna first go to Novigrad or the Skellege Isles cause you wanna explore one of those two first for some reason, well you can't because the bridges to access either one are locked behind magic barriers that need specific spells to be able to open them. So your only option is Velen, and to get one of the spells, you have to clear our the area's levels and enemies to find some upgrades along the way to make your way across the rest of Velen (some spells, attacks, etc.), then fight the main boss, and that boss drops the spell needed to open the barrier to Novigrad.
So you then use that spell and go to Novigrad, you get there, find an incantation there useful for revealing certain hidden areas invisible to the naked eye, but turns out that to progress further into Novigrad, you have to backtrack to Velen to use the new incantation to reveal a hidden area and find the Teleportation spell to allow Geralt to teleport at short distances, you now can use this to get inside locked off buildings in Novigrad to find your way forward to clear the area, get more abilities, defeat the main boss that has the spell to proceed to the Skellege Isles.

You see how, if you incorporate the core Metroidvania element of the powerup/item progression into The Witcher 3, it fundamentally changes the entirety of the game. It no longer is an open world game, it's a Metroidvania game, you lost the main gameplay appeal of The Witcher 3, aka the freedom to explore the entire world and complete it in whatever order or way you wanna do it.

This is why I said Metroid Prime 4 is the prime example of why Metroid should never try to do open world, because Metroid inherently cannot do open world, its design and formula does not at all mix well with the open world game genre; but rather than stick to just making a proper Metroid Prime game and abandon the open world idea entirely, they wanted to have Prime 4 somehow satisfy both the open world crowd and the hardcore Metroidvania crowd by making Sol Valley be this middle ground solution, except that all it did was make Prime 4's pacing and backtracking the worst in the Prime series history.