The biggest thing, as always, is if the non core audience will want to buy this game. You may as well as remove most of the mothers and responsible mothers buying this for there kids off this list. Even though it is rated Teen, mothers don't buy into shooting up things and people as good clean fun.
That mean you have the male demographic. The core that stuck it out this long will want this game or eventually pick this game up if they have nothing else to play or price becomes reasonable for a "unknown" new game. This leaves the guys who mostly play Tiger Woods and such on the Wii, which is coming out too close to this game. Then there is NCAA in July and Madden in August.
Plus it will have to sell the 2 million by Nov or Modern Warfare 2 will eat the rest of its lunch. That would be 20 weeks from launch date. Sega is not known for quick price cuts (see Valkyria Chronicles)
I'm just saying...
