Nobody asks Povetkin "Who you want to fight", its a decision that Sauerland makes. They are currently negotiating with 5 or 6 fighters (Holyfield, Dimitrenko, Mormeck, Rahman among them) and the decision on who will Povetkin fight next has to be made soon.

I bet they'll chose Holyfield. It's an easy win that will make some good money for Sauerland.
A Dimitrenko fight could make money in Germany too. The problem is that Dimitrenko is scheduled to defend his European title against Sprott on September 24th. He will have to cancel that fight if he wants a world title fight on December 17th.