It's going to fail, and I'm going to laugh.
There's no cooperative aspect to it (unless you play with a guitar, which would seem to require that you'd bought the previous games) which pretty much eliminates the "party game" aspect that made the previous games so popular.
The club-going scene aren't really much into games. They're too busy dressing like idiots, taking drugs that cause you to die of malignant hyperthermia, and waving glowsticks around.
Guitar players are impressive, talented people who create music. DJ's are douchebags who, at best, use other people's music to entertain people. At worst, they're morons who screw up perfectly good songs.
I think Activision realizes that buying the Guitar Hero name was a short-term deal. The people who actually made the game what it was have moved on and are now handing Activision's ass to them in the form of Rock Band. They realize they can no longer compete, so they thought this interesting little experiment up. I appreciate them trying to think outside the box. What I do not appreciate is the fact that their copycat mentality has rendered them completely incapable of actually doing so.