On that topic, and I also would like to get back to it, I agree with you.
The fact of being tempted is not sin, otherwise our Lord sinned in being tempted, yet it is clear from the description of His temptation that He never gave any room to the tempter.
We can also find many accounts from the Fathers of those who faced up to temptation and resisted manfully (and womanfully) not giving any room for temptation to find any place in the heart to take root.
I have been thinking about this on and off for the last few days, and in my own daily prayers from the Coptic Orthodox tradition we pray at every Hour, for those things
'...which we have committed willingly and those things which we have committed unwilling, those things which we have committed knowingly and those things which we have committed unknowingly, the hidden and the manifest.'
I have been thinking that in Christ He is always mindful, always recollected, or centred. There is no sense of sinning unthinkingly as I often do. He always knows what He is doing.
Whereas I will unthinkingly snap at some family member, He is never out of control because all of His faculties are ordered properly.
Back to the original topic, which I have also been thinking about. The Word does not take our broken humanity and dwell in it without deifying it, but this deification is a progressive process which comes to completion in the resurrection. But it began even at the Annunciation, and at the moment when the Word took the flesh which He created for Himself in the womb of the Ever-Virgin Mary.
So this does not mean that His humanity remains in the same entirely broken condition as our own, even though the humanity which He united to Himself is entirely that broken humanity.
Julian was wrong in a theological sense because he proposed that the Word united to Himself a humanity which was not broken and was not in need of healing.
But I believe that we would also be wrong to consider that the Word was bound by our infirmity in taking our humanity. Rather from the first moment of His incarnation He began to transform and renew and redeem our humanity, without it ceasing to be what it is, but rather making it what it was created to be.
I like the passage in the 6th council which says:
... his human will follows and that not as resisting and reluctant, but rather as subject to his divine and omnipotent will. For it was right that the flesh should be moved but subject to the divine will, according to the most wise Athanasius. For as his flesh is called and is the flesh of God the Word, so also the natural will of his flesh is called and is the proper will of God the Word, as he himself says: “I came down from heaven, not that I might do mine own will but the will of the Father which sent me!” where he calls his own will the will of his flesh, inasmuch as his flesh was also his own. For as his most holy and immaculate animated flesh was not destroyed because it was deified but continued in its own state and nature (ὄρῳ τε καὶ λόγῳ), so also his human will, although deified, was not suppressed, but was rather preserved according to the saying of Gregory Theologus: “His will [i.e., the Saviour’s] is not contrary to God but altogether deified.”
So our broken humanity was united to the Word but in being united began to be deified, and that deification is our own salvation.
Did Christ unite Himself to our broken humanity? Yes, He did. But did it remain broken when it became the own humanity of the Word? No, it began to be deified and renewed.