I am a longtime Metroid fan, and I disagree with the review of the single player portion of Metroid Prime Hunters. When I was playing it, I felt just as much like I was playing Samus as any other Metroid game. The fact that I was not reduced to naught and forced to find incremental upgrades over the course of the game did not reduce the Metroid feeling for me.
The additional weapons, in my opnion, are not simply interchangeable throw aways. The Battlehammer functions as a nice intermediary between the uncharged and charged Power Beam. The Magmaul makes a nice heavy hit comparable to missles if you're out of missles ammo. The bouncing and shotgun spread of the Judicator gives you a bit more leeway in your aiming. I could go on about the other weapons too, like how we have the first ever sniping weapon in a Metroid game (which is put to good use for puzzles). I found the inclusion of the other Hunters in the single player game to contribute greatly to expanding the Metroid Universe and make it feel more like a living breathing world. Now, finally, Samus has some competition!
I only have two complaints about the game. The first is not being able to view your scan log anywhere but in your ship (ARG!!), and the second is the generally simplistic nature of the environment puzzles. I can chalk these up to this being a handheld game, but by no means did I find it to be bad or un-Metroid-like. I even appreciated the fact for the first time in 4 Metroid games (Prime, Prime 2, Zero Mission, and Fusion) there was no stupid auto-help mechanism either optionally, or worse, forced on. I had to use my noggin a couple times.
Just because there is no lock-on and the gameplay mechanics are a little more straightforward of a first-person shooter type of game, doesn't negate the fact that this game felt completely like I was playing Samus in the Metroid universe to me.