Nearly half a year later, and EA has finally announced a date for Rock Band Wii. The press release was decidedly light on details beyond the fact that the Wii edition will include five "bonus songs." What about downloadable content? Online play?
A Harmonix rep has confirmed what I feared: Rock Band for Wii will not feature any form of downloadable content or online play for that matter. While I suspect Harmonix wanted to include DLC, Nintendo is likely not ready for it -- despite having announced DLC related plans during the Game Developers Conference earlier this year.
In a related forum post, Harmonix developer Sean Baptiste confirmed that the peripherals for the Wii version of Rock Band do not use the Wii Remote. Baptiste's statement seems to indicate that the guitar controller will not be cross-compatible with the Wii version of Guitar Hero III, which requires a Wii Remote to be inserted into the shell of the controller.
Rock Band Wii Arrives June 22, Will Not Offer Downloadable Songs or Online Play [ShackNews]