Except for the timelines, has the WBTS ever admitted it was wrong in any doctrinal matter?
I recall when I attended theology courses in college that one professor spent an entire outline on the meanings of the various words (Hebrew, Greek, etc.) meaning "spirit." He brought up the notion that spirits "sleep" at death and acknowledged that a case can be made for the "soul sleeping" doctrine. Yes, he said, these words can mean "breath." Even the Latin spiritis means "breath" and is the word we get "spirit" from. After covering the theory, however, he then approached it from the other end where, yes, on the other hand, it can mean spirit, as in that ethereal, fine matter type of being that is said to exist independent of our bodies. He covered the verse in Ecclesiastes, which he acknowledged was not an eschatological work, and talked about Jesus preaching to the "spirits" in prison during the three days in which his body lay in the tomb. These spirits were those of the disobedient who lived during the days of Noah. (The Witnesses say they were the mythical "sons of God" who turned themselves into humans and fornicated with the "daughters of men." But then why would he preach to them, even if that view is correct? (And there's much to suggest that it's a Hebrew misunderstanding of scripture.) It didn't make sense. Then Peter speaks of being able to remove the body as if it were a garment.
The bottom line was that while cases can be made for various doctrines, most Bible scholars, having looked at both sides of the issue, have come down on the side of the body having a spirit which animates it. And though arguments can be made to the contrary, unless one can speak to God directly and ask Him, it's anyone's best guess. So what if some Witnesses come to contrary conclusions regarding doctrines that aren't definitively answered in scripture? My point is, even if the Witnesses are correct about doctrines such as the state of man's intelligence between death and resurrection, there's not enough evidence to call it conclusive. (Personally, I believe the spirit continues on and that it existed before mortality, but others may come to other conclusions.) What if additional books of Christian scripture were discovered in some monestary somewhere, or in a jar sealed away somewhere? And what if they conclusively proved that the early Christians believed that the spirit of man didn't sleep? Could, or would, the JW leadership have the guts to change their doctrine? Or are they forever glued to it?