SFIC,standingfirminChrist said:He did not have the sin nature that was passed to all mankind. He did not have the wicked and deceitful heart that mankind has because of sin. He did not come forth speaking lies.
What you imply is that because Christ did not have a sin nature Christ was somehow incomplete, deficient, not a total man. That would make him imperfect and unable to fulfill the prophecy as a lamb unspotted or without blemish, and unable to be a sacrifice for our sins. In your theology Christ is disqualified to be a sacrifice for sins because he is not complete; he is deficient. He is not the perfect man of God.
Not having a sin nature (the Biblically correct view), in no way takes away from his humanity. His full humanity can be seen in his sufferings on the cross. Despite all of its detractions the play "The Passion" brought out in a vivid way the sufferings of Christ, as a man. He didn't have a sin nature; was perfect man, tempted in all poiints such as we are. If he had a sin nature then he wasn't God for God is not a sinner. He was perfect God and perfect man at one and the same time and remains so to this day.