Though there is really no reason to argue my point further, Metroid as an online FPS most certainly works and MPH is a great indicator of that. The only thing that really killed that game was Alt-Forms. If you played with other people who barred using those moves from the game in the capacity many people were using them, the game was a ton of fun. I'm sure something similar could've been included in MP3 and it too would've been fun. Sure it would've meant more development time, and that may not be feasible which I can understand, but to say that multiplayer just doesn't belong in Metroid is kind of ridiculous.
If I was to get a different FPS from Nintendo I would be pretty happy, but not getting online in Metroid is disappointing because it is a unique game that bears some similarity to an FPS that could have a very compelling online component that is like no other FPS out there. A Metroid online FPS multiplayer mode is far more interesting to me than some crappy online WWII FPS game, or that hunk of sh!t, Halo 3.