First let's looks at the time theory. We say that God is all knowing and yet we have the free will to make our own decisions. How can it be that God knows what we are going to do before we do it and yet He doesn't prevent or interfere with said actions? The only theory that makes sense to me is that God does not have time. Time is our measurement of things which he gave to us but which does not bind Him because he is above nature. Therefore, God sees and experiences all things at all times at one time. At this moment in God's experience you are reading this email, drinking your first bottle, watching your oldest child be born, pyramids are being built and some one is visiting your grave. Mary is watching her son die at the very same time that she is saying yes to being the mother of God.
The main thing that God wants is for us to be with Him in Heaven. However, remember that God is supernatural and we are natural. Therefore we have no place in Heaven as a natural beings because it is a supernatural place (place isn't the best word but I can't come up with a better one right now).
Our tendency to sin is also a natural tendency not a supernatural one. There are consequences to our sins. It distances us from God.
God promises justice and He will not go back on His word. God can not be contrary to Himself. Therefore there has to be a consequence for sin in order for there to be justice. He can't simply say, "Oh well". So what is God to do if the consequence of sin is separation from God but His will is for us to be with Him? He needs to have a way to ensure justice along with bringing us to Heaven. But only the supernatural can enter Heaven! Yikes! Sooooo He shares His supernatural nature with our natural nature and becomes Jesus. This way man can enter Heaven because Jesus opens it up for him. I usually explain it like the supernatural is carrying the natural through the hatch into Heaven!
Ok so why did He have to have to die? Because man dies. This is also a consequence of sin. We read this in Genesis 3:13 when Adam is returned to the dirt. It is the nature of man to die. Since God created man and nature and we have already stated that God will not be contrary to Himself, He needs to follow the natural law which He created. The only way to follow both His desire to have us with Him and the need to continue with the natural law is to conquer both at one time. Hence he dies, as man and ascends into Heaven as God as one person in Jesus. Whew. (It's as if a judge has to sentence his son with a death penalty but then takes his place on the chair because he wants his son to live)
So why such an ugly death? Excellent question. We have already stated that man's sins distance us from God. God is the only one who can forgive us the sins against Him. He alone can take them and wipe them out and He is just. In Exodus chapter 21 we read the passage about an eye for an eye. We take this to mean that there needs to be a somewhat equal penalty for an offense. We also say that Jesus died and rose to save all men from all sin. We can safely say that if our time theory is correct and Jesus is dying and rising for all ages and all sins are happening at the same time in His experience that the just death had to be extreme in order to equal or to get close to the sins being committed. His death is the ultimate consequence. The next question might then refer to Matthew 5:38-42 where Jesus tells His apostles to turn the other cheek instead of retaliating. Jesus is speaking with authority over the Old Testament law. He does this because as God He has authority and because He knows that it is His upcoming sacrifice that will bring justice to mankind. This does not mean that man does not have the right to apply consequences for crimes but that the consequence of death has been taken care of by Jesus.
