It was good to see Soundgarden back and it was as if they had never been away. Keith Emerson made a comeback of sorts, with The Three Fates project, so I would like to see him hook up again with Greg. Focus came back with the X album, but without Jan Akkerman. Perhaps they could coax him back for 2013.
Stone Gossard returned with Brad, but I have not heard the United We Stand album yet. The Cult's Choice of Weapon was a diappointment to me, as was ZZ Top's La Futura. I haven't made my mind up about Rush's Clockwork Angels, suffice to say that I enjoyed the Deluxe Edition of 2112 much more.
The biggest disappointment of 2012 must be the apparent demise of Black Country Communion, one of the best hard rock bands in years. For 2013, I am hoping that Tony Iommi's health improves, following his treatment, and that Wilco Johnson has a positive year despite his illness.