The last 3 console metroid games have gone downhill. I still enjoyed metroid prime 3, but the first two were way better. I've heard people bitch about the ammo in echoes, but that really never bothered me too much. What made the first game great was that you felt truly alone on tallon IV. You explored the planet of an extinct civilization whose very ghosts were trying to kill, all the while fighting off space pirates and death parasites that no one understood. You had no allies, and yet you had to move into the unknown for the game to progress.
In the second game, it was more of the same. You HAD allies, but they all died before the game started, and the race indigenous to aether was only ALMOST extinct, but the game still did an exceedingly good job of creeping you the fuck out.
In the third game, you had friends all around, and could even call on ship for help (and your ship practically had a personality of its own.) and you knew exactly what you were up against from the get go.
Now it looks like you're playing on a world inhabited by your own species, in an environment familiar to you, your own turf. Two predictions: One, the government fucks you over at least once, because of a power struggle or some other buttfuckery. Two, the space pirates invade the human capital world. Watch as these both come true. They're completely changing the paradigm of the game.