Honestly, part of the reason my expectation for Sanderson's attention to detail was so low was due to how quickly he re-read the entire series. Remember when he used to give us percentage updates concerning his re-read?
I don't doubt he's a fast reader, but NOBODY can read at that speed AND pay attention to close details. It just doesn't happen. He zipped through the series in a week or two if I recall, and I remember thinking to myself, "How can this guy be digging deep enough into the novels after such a superficial read?"