I couldn't agree more. Every time I see him at the 4, I am absolutely shocked that OKC was able to be a playoff team starting him at that position. It just shows how good Durant and Westbrook really are.
This guy is a classic "power 3". When he is playing the 4, he doesn't have the size to play in the post, and he doesn't have the handle to take advantage of his speed advantage on anything other than the fast break. However, when you put him at SF, he has the quickness to cover his man (and his length helps as well), but offensively, he can really take advantage of his size, and his low post game against the smaller defenders.
Luckily, this morning on the radio, Doc made it pretty clear that he felt Green was a SF as well. He said that it was good that they had him to cover SF's playing PF, like Thadeus Young, but other than that, he really is best suited to be playing SF. So, I imagine we will be seeing a lot less of Green at the 4, now that they are getting healthy up front again, and are not forced to play him there out of necessity.