Durant is the focus of the defense almost every night and is scoring 19.5 ppg as a rookie on a terrible team. I'd consider that way above average.
That makes it more impressive? I don't think Durant has been a particularly strong focus of defenses. He's not a post up player, or a strong dribbler ... yet. I've only watched a few Sonics games this year, admittedly, but I don't recall defenses keying on him like he's a big threat. He scores a good number of points, but there's a difference between scoring a lot and getting your team more points than they'd get otherwise. He doesn't appear to make his team any better at this point. That's typical of most rookies, though.
I guess that means there are quite a few rookies this year that you would trade Durant for straight up? Why don't you give us a list of 10 if he's only above average.
He's come a looooong way since the beginning of the season. His passing and floor vision have improved dramatically, along with his shot selection. It helps now that Wally is consistent because earlier in the season, teams would crack down on KD late in games and completely shut down the Sonics offense. It was painful to watch. Now their offense is more varied and effective, which has allowed them to win more often.