Now I only played the original old school Metroid so I'm not totally sure what has changed over the years, but I felt like throwing in my bit.
First of all, Metroid (as far as I know) has ALWAYS been a 3rd person game. Making a 3rd person game into a FPS has always seemed difficult, if not impossible, to do without losing some of the atmosphere of the game. Can anyone else imagine a first person...Castlevania? Yeesh it would just look like a bunch of updated Doom rejects wandering around a Wolfenstein castle. However, in 3rd person the Belmonts (and other characters) seem more tangible. Same with Metroid. When I think Metroid, I think of a little armored figure running (and rolling) up, down, and across my screen. Trying to put me into Samus' boots makes it seem almost generic. All the music and particle effects won't change the fact that it's basically the same as every other FPS. Again, this is just my opinion and hey, I personally liked Halo and several other FPS and may even check this one out once I get done playing Vice City.
BTW: sorry Miyamoto but if the players' point of view is as the main character and the game involves destroying other characters in the game, it is a first person SHOOTER, not an FPA.
also BTW: I check out Gamefaqs when I'm stuck at a certain point, but the message board looks like it's been overrun by 13 year olds and people who think that games should be able to be beaten at one sitting.