Manhunt 2 is a niche game. It may sell as little as 75K on Wii, or as much as 250K. The original was not a hit on PS2, and this time there are multiple versions spliting up that small audience.
No More Heroes is also a niche game, which wouldn't have much of a shot at selling 1 million copies on any system.
Project HAMMER involves a robot with a giant motion-controlled hammer. I guess that's a "mature" game. Uh...
I really don't know what to think of Disaster: Day of Crisis, but it may well be a Teen-rated game.
RE:UC is an on-rails spinoff, and RE4 is the 4th version of a several-year-old game.
Red Steel will sell over 1 million copies, but it is rated "teen."
Basically, none of these test if Wii can take "mature" games. If a major "mature" game like RE5, MGS4, GTA4 or Halo3 came to the system, I'm pretty sure it would sell pretty well. Developers are cautious about bringing those games, however.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.