ExB: If it was by design (hypothetically) and the Bible is the designers word, and JWs seem to be the closest to it,
Seem? So, no one would know for sure, but we could be confident that JWs had the best take? We would need to determine how it is that we can consider them the closest to that true understanding.
If it was by design, and the designer wanted something specific for/from us, I would expect that designer to make it obvious. By showing up and explaining it all, and perhaps by writing the holy book himself, thus providing us with a clear guide that isn't subject to constant interpretation and reinterpretation for centuries on end without any hope of a resolution.
If the JWs were the closest to the truth of the designer, then I would hesitate to change anything unless I understood what it was that made them more accurate than anyone else. Otherwise, we might be moving away from god, not towards him.