I see him as like a Samuel Peter/ray Mercer/Jerry quarry level. World class, capable of being a titlist depending on circumstances, but was never gonna be the top dog in the division.
I will say this for your position: Klitschko didn't even rate Povetkin among the 3 most skillful fighters he'd faced. Byrd didn't rate him above Holyfield in skill. He didn't show up anywhere in the "best I've trained" for Teddy Atlas, either, and Atlas was reminiscing about obscure people like Kallie Knoetze. Witherspoon made more of an impression on his "Best I've Faced" opponents. I hesitate to draw much of a conclusion from the absence of evidence in the haphazard Ring interviews, but it is kind of interesting.