You were saying ...
If God is omnipotent, why could He not know how to let Job grasp that fullness of understanding?
God has given mankind a "progressive revelation" of Himself and what He's doing, from the time of the Garden of Eden to the present time. And we're still not in the fullness of understanding, even at this point.
There will be a fuller understanding in the future, from here forward, just as there has been progressive revelation to us from the past up to now.
During the Millennial Kingdom here on earth, the fullness of the knowledge of God will expand greatly and be much more than it is now.
It's like asking -- when reading a book -- "Why don't I know the whole story right in the first chapter?" Well..., you'll know the whole story when you get to the end of the book. We haven't gotten to the end of the book yet -- the book that is mankind's history and how God has interacted with mankind from the beginning and all the way through to the end of the Millennial Kingdom.
The problem with that view, which I understand to be at the heart of dispensationalism, is that it means we are being judged based on our reaction to incomplete information...information that is not revealed to us. When we compare to human institutions, is it not closer to the horrid regimes of man's history, where one could not have access to the evidence of the case, rather than what we see as a better system?