Are you absolutely positive about that? Or did other players climb and push JW down? Awfully tough to stay at #16 overall. I'm not sure we can assume it's because of an anti-Iowa bias or something like that.
Not saying you're definitely wrong, but these things aren't static. Some players can really blow up and others maybe peak sooner. I don't follow high school basketball much, though, so I can't really talk about why JW might not have stayed #16.
Not positive that's the entire reason he moved down, but I would have bet my life savings on him moving down after he committed. I also am positive that recruiting rankings have a lot to do with what schools offer. That being the case, it's virtually impossible for a class ranking to be skewed at least some by the name on the front of the jersey.
Take Alabama football for example. Clearly if a kid receives an offer from Alabama, recruiting services will take notice and rightfully assume the kid deserves a higher ranking. Alambama could legitimately fill an entire class with unheard of kids and end up with a top 10 class when all is said and done. That is the extreme example of it. But without a doubt that happens. And knowing that happens, it is pretty apparent that recruiting services have a pecking order of programs, and the team rankings are highly influenced by that pecking order.