Producer for the Wii version of Dead Space, Steve Papoutsis, has confirmed that there currently aren't plans for DLC.
Despite Nintendo including support for high-capacity storage via SDHC memory cards, EA don't have plans to take advantage with additional, downloadable content.
I don't think we have any plans for that right now. It's interesting but no.
Speaking to VG247, Papoutsis also reiterated that the game won't be a "watered down" experience, staying true to the original.