Oh i forgot to say some things about the bass that makes it a little bit more interesting
Bass now has its own guitar
There are basicly 6 buttons now, you have the regular 5 but now a white line will scroll across the fretboard indacating an open-string strum (no buttons)
edit: some things about the drums
star power is activated by a solo fill followed by hitting both cymbals at the end
when playing solo drum career, during the enchors you will get to have your own kick-ass extended drum solo in the song