I fully admit that the only reason I pre-ordered this game is not just because of the $20 credit on Amazon, but also because I still had the $20 credit from Super Mario Galaxy 2 and didn't see anything else I wanted to spend it on. Otherwise, I would have waited until the reviews were out before making a decision.
That said, I still am hopeful of this game. I'm not one who has a set idea of what I think a Metroid game should be, so I don't mind if the usual formula is changed up. As much as I liked the Metroid Prime games, there have been three of those, and so I'm ready for something different. However, I haven't really been keeping up with the info on this game, so I don't know much about it outside of what I've gathered from the comments of others.
Also, I said this in a less trafficked thread, so I'll repeat it here. I've always felt that, out of every Nintendo character, Samus would be one of the best ones with which to develop a character. There's really nothing established about the character of Samus, we barely even know what she looks like outside of getting a glimpse at the end of each game, much less where she came from, how she came to be, and what are her motivations. This isn't like with Mario games, where a story isn't integral to the experience, or Zelda games, where the stories are really about the worlds rather than Link himself. The settings and goals of the games can mix well with giving some backstory and developing a hero. That's one reason I liked Fusion, it gave me something, not too much, not too little, that made Samus feel more human rather than as robotic as her appearance.