I think the only question we can answer right now is whether he's consistently dropping passes. And the answer to that is no.
Williams' preference is to body catch. I don't like that, but unless it becomes a bigger issue than dropping an occasional pass, like every other receiver, then I'm not going to get too upset about it. Being a good, reliable receiver is less about how you catch than being open and making the catch. He dropped one that he should have caught and wasn't able to bring in a contested high throw that plenty of receivers have trouble catching, like Dez letting the high screen pass from Romo go through his hands.