It's understandable that someone who is skilled enough to use a real instrument and talented enough to make music in an actual band could grow tired of the "rock and roll simulation" genre, but I whole heartedly disagree with the comment that the theory concerning giving the opportunity to create music to those who can't is bullshit. I think Harmonix has nailed the formula, but there still is a large gap to be filled by the player's own imagination.
I would reference the photo in the article that shows the small trio playing Rock Band. (I also understand that the photo may have been staged for illustration purposes, but bear with me) One is sitting down on the couch, there is a baby sitting nearby, which is totally fine, but this more than likely means that the singer and general conversation has to be kept at a reasonable volume, and the drummer is far removed from the group. In the scenario, the players have taken all the game has to offer, but has given nothing back.
Call me obsessed, but I bought a mic stand. I felt that the singer at our house wasn't ever really feeling like he was part of it, so the stand helps him feel more connected to the group. I bought the drum silencers (greatest things ever, by the way) to help the drummer feel less like he was hitting buckets. And my friends and family fill in the gaps. We move to the beat, we sing along when we know the words, sometimes the guitarists will go back to back while rocking, we treat the people waiting for their turn like audience members, we jump simultaneously to a heavy down beat... in short we rock. We may rock like the biggest dorks on the planet, only emulating what we think should happen in a rock band, but by using our imaginations, getting over our pride, and enjoying the feeling of the music, I would like to think that we fulfill Harmonix's mission statement.
(That all being said, I am running out of places to store all my plastic instruments when non-videogame based parties happen.)
