This is becoming a rather silly debate. Yes, if we ignore FG% and focus on point and rebounds per 36 MPG, Big Al and Sully are roughly on par. But by doing so, we are ignoring not only a big stat, but two other things:
1) As many have said, Big Al had world class post moves from the get go. And that's a rare commodity in the NBA.
2) Big Al can legitimately play center (in fact, he is a center now). And while the C's played him out of position there this year, Sullinger is not a center.
Because of those two things, Big Al's value was much higher than Sully's is now--and that's not even factoring in lingering concerns about Sully's back.
That said, Kevin Love is not as good as KG was in his prime (and probably never will be) and the C's face the added challenge of trying to work out an extension with Love (something that wasn't a concern with KG). So I think we can look at them somewhat comparably in that light.
But I don't think people should be expecting the Wolves to be as enamored with Sully as a prospect as they were with Big Al.
Sully's a nice player, but his upside is probably something around Carlos Boozer--which is nice, but not a player who is going to transform your franchise.