I think getting more core games selling is something Nintendo will have to work on with Wii 2.
The Wii is in some ways a test run for Wii 2 I think, they needed the Wii to reinvigorate their brand. Next gen with third party support from day 1, they should have an easier go of it.
That said, Dead Space wasn't a big seller on the 360 to begin with, and odds are a lot of fans were not pleased with the decision to make a on-rails spin off of the franchise either.
I have a feeling Resident Evil: Darkside Chronicles will sell a lot better.