Also, he really didn't die, right? Unless he is gone from the universe completely, never to be present again. In your terms, it would work like this: Kidnappers take my son and demand $100,000 for his release. I give them the $100,000, get my son back, and then print $100,000 on my money machine at home. So basically I did not lose anything.
So if I chop off your finger and they sew it back on, I didn't really hurt anything?
I'm sorry but this is so far fetched. Why would god need to die for us - he's almighty, right?
The official answer would be "to preserve justice" --
However it is that he chose to provide a way for us to get to heaven, I'm just glad he did it. If God makes rules and that means he wants to follow them too .. whatever... He's God. He can do what he wants to.
I wonder sometimes if he just wanted to see what it was like to be fully human so he decided to be a sacrifice and keep the justice rule alive. Maybe we'll get it once we get to heaven?