Several hours in: put me in the "fucking awesome" camp.
The main thing is that I honestly think many people are going to hate this game because they will be 100% determined to experience it as a different game than what it is. This is not Super Metroid, it is not Metroid 5 with Shadow Complex style 2.5d gameplay.
And it is a crime if someone bitches that this game is janky, awkward, or "doesn't work". This is one of the most polished gaming experiences this generation. EVERYTHING is like butter, everything feels as if it has been gone over with a fine toothed comb. Nevermind the god damned first person transitions all the wailing is about. Every door load, cut scene transition, enemy encounter, sub-boss introduction, weapon switch, item get, unobtrusive tutorial messages that don't pause the game and don't interrupt your play. Every aspect of the technical quality and the game's raw programming. This /is/ a "triple A" game by this generation's standards and the art style works so well with the graphics that like Super Mario Galaxy, upscale it to 1080p and LOL @ Wii graphics complaints. It looks better, is modeled better, and is designed better than most (not ALL, simmer down boys) games that have come out on the HD consoles. And it animates incredibly, with Samus being the star of the show.
Basically, this is what Team Ninja buys you - incredibly solid feeling gameplay, a world that clicks under your character's feet and feels real, inventive and demanding combat (LOL @ auto-aiming is n00b mode), and style.
About the d-pad: I've no problems with it, and I wonder if some people are going to make themselves suffer by trying to jam the d-pad around as if it's an analog stick trying to "be precise". Samus is on a variety of grids and movement splines. The game plays like butter and there is no ambiguity about how you are moving in 3D space. There's so much work put into making sure the playing experience is enjoyable and fluid it makes a lot of other games look like janky crap.
What I will say about the first person switch and missile usage is that it's brilliant but some folks are going to play this game wrong. Reviewers who whined for an analog stick to turn this into Metroid Prime entirely missed the point and played a different game. This is Ninja Gaiden in Space: you are not supposed to go visor and run around like Master Chief shooting willy-nilly. You are supposed to execute the correct counter play to what each enemy (or group of enemies) does and visor look w/ missile lock-on is one of those moves. Complaining that this isn't an FPS in visor mode is like playing Vanquish and saying it sucks because you can't play it like Gears of War. Different games, get over it, learn how to play.
Most of all, the first person stuff may in fact (so far) be slightly underutilized in some ways. There's room for many more awesome sequences such as the elevator. The visor mode allows Metroid Prime's legacy to not be forgotten and contribute something significant to 3rd person Metroid. (Speaking of polish: the freakin' UI smoothly wraps around your visor when going in and out of first-person view. There is not a detail in this game that hasn't been coated with turtle wax.)
Much like Mario Galaxy 1, there are areas that are rougher than others, but again, I can see how this game is honestly blazing new territory. If another game is made that takes cues from this design, the potential for polish is immense.
I'm not even going to get into the story because others have discussed the reality (versus the negative hype) of the story's good and bad points, and it's STILL much less groan inducing than MGS4 and FFXIII. Maybe I just don't have preconceptions of being Samus' boyfriend, so I'm not obsessed with the character, but I even have grown to like the story and the characters halfway through.
PLAY MOAR NAO BYE BYE
EDIT: Okay and yes to balance my immense excitement that the game doesn't disappoint after all, I will fully agree the music is bizarrely underutilized. What is there is good, and there are many places where they could have used a lot more of it. But even so, in the big picture, it's a small thing.