The big hands issue is one of those classic "miss the forest for the trees" scenarios, in my opinion.
Suppose that we posit that ability to shoot, or ability to learn to shoot, is evenly distributed throughout the populace. Seven-footers are pretty rare. You can't teach height. The need for bigs and the limited pool of the tallest ones, forces you to accept bigs that can't shoot, to take advantage of the other things that they bring. There are plenty of six-footers that can't shoot, either, but six-footers are a dime a dozen and as a result, the ones that make it into the NBA are usually the ones that can shoot, or otherwise have some exceptional ability that makes up for it (like Rondo's court vision, instincts, and passing ability, for instance).
This makes more sense to me than "big hands". Also throw "shallower angle" into this pile while we're at it. The point is that we're talking about marginal things, when there is already a pretty plausible explanation.
In other news, Rick Barry. How many bad free throw shooters would see better results if they just tried something a little unorthodox?