To understand what makes a good Metroidvania - that is, a game that gives people choice and room to explore without leaving them feeling lost and powerless - it helps to examine some of the games that helped inspire the genre. Like Metroid 1.
One of the fun aspects of Metroid was how it quickly and neatly communicated how you were supposed to progress. Can't crouch through this gap in the opening rooms? That's because you need a powerup — oh look, here's the Morph Ball.
But not all powerups were necessary to explore throughout the world. They made the game easier, which was great because Metroid was bloody tough back in the day. You could fight bosses in the order you chose, and there were multiple ways to reach them. But the non-linear nature of the game and how much the world opened up, not to mention the incredibly obscure secrets, makes it a bit harder to play in 2018.
Metroid 1 is still critically important though, as was the changes Nintendo opted to make with Metroid: Zero Mission for the Game Boy Advance in 2004. The world was much more restrictive, opening up a lot less with each powerup you find.
It's more linear, which has the benefit of helping users get lost less. But that also means the player ends up with less choice, there's less agency in exploring the world, especially when the game starts giving you direct waypoints through Chozo statues.
YouTuber Mark Brown makes the argument here that Metroid: Zero Mission was an overcorrection in this regard: by leading players by the hand too much, they lack the encouragement needed to prod and poke the world in the ways necessary to find the secrets that it holds. While Zero Mission does have lots for players to discover, they tend to take the path that's first offered to them - if they progress through the world at all.
It's a fine line: how much assistance do you provide to stop players from getting fatigued and dropping the game altogether? Metroid: Zero Mission was very much a product of its time, as was Metroid 1. But it wouldn't be until Super Metroid that the designers found a much better balance between leading the player and accounting for the different ways in which people will play the game, with subtle hints and design cues throughout.