It looks like disappointing sales of games Dead Space Extraction, Madworld and House of the Dead: Overkill have caused second thoughts for Sega on the mature game market for Nintendo Wii games.
In an interview with 1-UP a Sega spokesperson commented...
Are we going to do more mature titles for the Wii? Probably not. Look at Dead Space. We were stunned. That was my litmus test. Basically, it’s like, okay, you got EA, who can put all the marketing muscle behind this, an established franchise that scored quite well on 360 and PS3. They should be able to actually hit this out of the park, right? We get numbers, real numbers aside from NPD, and I’m like, ‘Woah’.
Source: 1-UP