Those announcements all got flack for being light on substance and a logo without a developer is still much less than the others.
I get that it's very light but to a big fan the mere confirmation of existence is enough.
People got teary eyed just because the saga of Shenmue would continue, even if they intellectually knew that it wouldn't be at the levels of Shenmue 1 + 2 budget wise.
And Metroid has been handled as the red-headed step child and only been given token acknowledgements by Nintendo for a long time so seeing even just this logo means a lot. It confirms a new entry.
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As I read every post in the voting thread, there are posters that seem like fans of Metroid that feel the same you guys do as they wrote in comments that they didn't vote for Metroid Prime 4 because it was merely a logo.