It would be a Wiiware game(downloadable only)
It would be online only!
You could level up and customize your character.
First Person View
You could win new blasters, projectiles, powerups, and sheilds as you get your rank up.
You can start clans and have wars with up to 32 people.
You could also unlock online minigames like mii target practice(in which you would shoot the very miis that you create)
You can have a custom character, but in the act of a quick game you can choose from a default list of hunters(Samus, Trace, Noxus, etc)
Maybe you could even download new levels and equipment from the Wii Shop!