Isaac doesn't amaze me either. Tweener alert! D-Will looked better than him before the draft.
I don't think he'll be big of a factor on offense in the nba very soon his skillset there makes him more of a 4 while his defensive potential might be better fitting as a 3. This a bad combination. A Shawn Marion doesn't come along very often. His advanced stats are promising though. Sometimes you have players that are better than their advanced stats but you rarely have players that are much worse than their advanced stats (DRPM might be the exception).
Isaac isn't what I would call a tweener, a tweener is someone too short for their position. Isaac has legitimate height and length for a PF. And yes Derrick Williams may have looked better in college and so did Michael Beasley, but those were legitimate tweeners.