Due to technical or licensing restrictions, the DLC offerings will not be the same for every console platform. For example, certain artists prefer to keep the integrity of the track pack rather than releasing singles and the Wii’s infrastructure only allows us the ability to release single songs as DLC. We are very excited to be the first third-party publisher to bring a library of playable DLC songs to the Nintendo Wii platform. Vicarious Visions has pioneered with Nintendo a seamless way to download, store and access songs via SD Card. The development team is committed to offering Wii fans worldwide as much variety of DLC as possible on a regular basis. – Activision statement

See Nintendo, lack of a adicuate space is hurting the Wii and it’s users.

Link