Wlad, but I doubt he'll unify. Most likely, he'll do just enough to be considered lineal, and even that will take a couple of years.
Even though I am a huge fan, I doubt it. Given his age and vulnarability to injuries he will probably retire after capturing a belt again. I think Povetkin has all the potential to be a dominant Champ within a couple of years. The only threat to him IMO is Solis, given he really gets into a good shape and stays that way.
