I'd guess they didn't see any developers using a mic anytime soon...it could be a very tiny add-on to the bottom of the Wiimote...but then you'd have to hold your Wiimote upside-down...
LEFT4DEAD411.COM
Bet with disolitude: Left4Dead will have a higher Metacritic rating than Project Origin, 3 months after the second game's release. (hasn't been 3 months but it looks like I won :-p )