Probably 2-4 on offense, and mid pack (maybe 60th-90th) on defense, but getting better through smarts and positioning.
Somehow, the 2-4 on offense pulls him way up from the 31 average of the two rankings, because the offensive part can't be taught, and is highly sought out. On the other hand, size can't be taught either, nor big hits, etc. He will never be the true prototype no. 1 like a Chris Pronger, Chara, etc., so we can't rank him that highly just because of offense.
So, 15 seems about right to me, too.