If any game should be full mulit-platform it should be rockband but I do sorta/kinda/though not really get what they are saying. The Wii was top dog against the HD-twins yet rockband still actually sold more on the HD-twins together. Now that Wii U is definitely third place Wii U it's entirely plausible that the game wouldn't even be profitable. Keeping in mind that there are likely separate royalty agreements that need to be made for each platform _per song_.
Still I think it would be worth the potential risk, even though I would definitely not buy it on the Wii U.











