Anyone can be there from day one but the fact is Gunpei Yokoi created Metroid the ain't no two ways about it no matter what spin you use, no Yokoi no Metroid, Sakamoto has been in the loop for long because he was one of Yokoi's top men. Yokoi had Makoto Kano design the Metroid series concept while someone else did the art design under his direction, using the combined concept Yokoi then task R&D1 now intelligent systems to created the first game and had Sakamoto one of the more senior designers direct the game to the concieved concept, Metroid is as much his as Zelda is Aonuma's, they worked on the series they direct work on for ages but it doesn't mean they created them.

That's like saying Yokoi "created" Donkey Kong and Mario Bros.  He was the producer on all these games.

Miyamoto was the designer/director for Donkey Kong and Mario Bros, Sakamoto was the designer/director for Metroid (with Kiyotake).  Kanoh only did the script/scenario for Metroid, none of the actual game design.

Who said anything about producing? I'm talking solely about creation which Yokoi did with Metroid, Miyamoto created DK and Mario himself, Sakamoto may be the driving force but the fact remains he didn't create Metroid Yokoi did. Kanoh created the basic concept under Yokoi to give R&D1 an idea of what the series would be about, it was through this that Sakamoto concieved the gameplay mechanics to use which is why Kanoh took over as producer for Super Metroid after Yokoi left.

Sakamoto did the game itself. He (and Kiyotake) "created" Metroid in the ways that really matter, including Samus herself actually.  And the most loved installment (Super Metroid) was really his crowing achievement, with Yokoi barely even involved.

Yokoi didn't "create" the world, gameplay, story, characters or music in Metroid.  Kiyotake, Sakamoto, Kanoh and Tanaka did.  So what exactly did Yokoi "create"?

Actually Yokoi was more involve then you're trying to make out or want to admit, he concieved the idea of a free roaming game which focused on exploration after seeing Zelda from his protege Miyamoto as he liked the concept and one he would use often later on, he then tasked each of the people you've mentioned to help him design and created the game. He would have them come up and take ideas to him which he would decide ultimately which stayed and which didn't and decided the overall direction for the final concept before it went into development, everything about it's creation was done under his direction. To describe this best to you Yokoi was like a conductor while they are his orchestra, by themselves Metroid would never had surfaced as one set of intruments can't do an entire orchestra but he utilized their talents to create the franchise much like a conductor uses several groups of instruments to create a piece.

To understand this you need to know how development goes for some designers, some of them have an idea and take it to their team to help further it, when the idea is presented to the team they will share ideas and the designer will focus on ones that stick close to his/her vision, this is creative directing and Yokoi used the traits and talents of his team to help bring his idea of a game based on exploration to life so yes we can credit him as the creator like it or not.

I fully understand the role of producer, and how this role tends to get exaggerated when it comes to Nintendo in particular.  Miyamoto being a good example actually.

I honestly have no issue with Yokoi being considered the creator of Metroid.  What I take issue with is the notion that Sakamoto isn't, when he was the chief game designer, or Kiyotake when he literally created Samus Aran.  Like it or not, Metroid has more than one credited "creator".  And Sakamoto's put more into the series as a whole than anyone else.