Activision has been exploiting franchisees like Guitar Hero, Tony Hawk and Call of Duty for quite some time. It makes sense if they yearly release newer CoD or Tony Hawk game but it is shear stupid to bring out Guitar Hero every year with same gameplay, graphics and different songs.

It has been reported that people at Activision are already testing Guitar Hero IV. It is quite shocking that instead of releasing new download add-ons they are launching new game which probably will be same as Guitar Hero III.
As it's not an official announcement, so it is possible that testing is not for Guitar Hero IV but testing related to new download add-ons.
Let's hope that it's all about add-ons and they really bring out some cool downloadable songs for existing version.
Via: G4TV