I think it has a very good and fair DLC model. Especially with the carry over from previous generation Rock Band games.
The last point about charging twice the cost of the song is ridiculous. You aren't just buying an mp3 are you? Harmonix have created the track 'level'. And I would assume the artist/label get more money for these rock band tracks than an mp3 sale, in the same way as it doest cost $1 to put a song into a movie/advert/game etc...
PS, PS2, Gameboy Advance, PS3, PSP, PS4, Xbox One