I realize this may come off as 'trolling,' but I think Ennis coming from Villanova (slightly superior program) hurt Purdue's chances (to Octeus, Purdue was a definite step up). For whatever reason, I get the feeling that the other schools he listed, seem to be more 'attractive' programs right now.
I know Purdue's bball program, without a doubt, is better than Tennessee and Oregon, but even those programs seem to be able to attract top-level talent.
Regardless, I think Purdue will be fine. PJ is a year older, and Weatherford should provide a defensive spark and an 'in your face' attitude out on the court.