You can only randomize so much when a linear game has a set path. You can't get anywhere in Samus's first ever visit to Zebes if you don't get the Morph Ball you can't do anything in Metroid II until you kill a few metroids, and you need the requisite items to do so. When you venture through a randomizer version of the original Metroid or Metroid II: Return of Samus you still have to follow the bounds of the game. Thing is, though, that randomizers have to work with the existing code of the game, and despite how much they can change up often they're limited buy the vary construction of the world being explored. That is the power, and beauty, of the form. When you've played the vanilla game enough times that you have it all down in your memory, a randomizer can reveal things you never even realized about the game in new and intriguing ways. They help to create a new experience even as you trudge through familiar hallways and areas. They take what's already in the game and move it around, be it items or enemies or what have you.
By definition randomizers randomize games.
