Here's my theory:
Christ's incarnation existed in an instant in time. By taking on physical properties, Christ was not "omnipresent" during his sojurn on earth. The Father and The Holy Spirit remained in "eternity" and thus were possessed with all knowledge and all power. When Christ said that he only knew what the Father revealed to him, was he telling the truth? When Jesus said that he did not know the day or the hour of his return, was he telling the truth?
So the question is why, at that moment "in time" did Christ not know the future? Because at that moment he was dewelling "in time" and not in eternity. Thus he could not independently know the future, because from his point of view, it had not yet happened. But from the Father's point of view, from the eternity point of view, the future was certain because the Father was there and the Father knew it.
What's your theory?
I don't have a theory... just a lot of questions. Your theory I think does damage to the incarnation. If Christ was fully God and fully Man... then your theory would appear to suggest that Christ was incarnate before Christ was incarnate. I tend to lean toward a kenotic view of the incarnation for those reasons you expressed and others. Yet, we must be careful not to divorce Christ's Godhood from his Manhood. Interesting theory.
My theory is that your theory is based on a misuderstanding of Scripture.
If you look at the Greek, the better translation of the word given as "know" is almost certainly "make known".
See this analysis: Did Jesus Not Know the Hour of His Second Coming?
That said, of course, it is a given that Omniscience is a function of Christ's Divine Nature, not a function of His Human Nature.
However, when -- at any time during the Incarnation -- was the Person of Christ separate from His Divine Nature? Answer: NEVER.