ah, there's that free will thing again. God could MAKE us anything.
Sometimes we still see things as being separate, HEaven is UP THERE and earth is DOWN HERE and Hell is DOWN THERE. Well, God is IN US. And here's a confusing statment... we are made perfect by Christ's sacrifice. ha, go figure that one.
I think death is a natural consequence here, not God saying it's His chosen punishment. And death is maybe the death of spirit or the death of loving and being and contributing. We all are naturally prone to sin. Jesus became completely like us, even as far as experiencing being a fetus (think of that next time you debate abortion issues), and He experienced all our human feelings and experiences. He lived perfectly and was an example... now, can we hope to achieve perfection in our life - no probably not... but we can always grow and strive to be like Christ. And Christ is within us so we are able to tap into Him for guidance and direction.
That doesn't really answer your question though. Why did Jesus have to die. Well, think of Him as the Lamb... the perfect sacrifice, the perfect Lamb of God... flawless sacrifice. The new covenant, no more sacrifices, the ultimate one was given. I believe when we are told there is no greater sacrifice than to give ones life for someone... I don't think this means to die for them or to protect them... I believe it is to lay down your life - to live for them, not for yourself. To serve them, not yourself. I think this taps into what Christ did, he served us, gave himself to serve as sacrifice for us, or for all our collective sins. He became our way to salvation, no longer animals, we were given a direct relationship with God to become one with God... like dialing direct now.