| Just dropping the Israelites in their midst would have been disastrous. The Israelites would have been forced into a war with the Canaanites before they were ready and the end result would have been a composite culture instead of the culture set apart that God desired. That would have also provided large scale proof that God exists, which has its own problems.
People have a good idea which aspects of God to emulate. People should love each other, just as God loves them. People should not demand worship even though God demands worship.
The burning bush was God telling Moses to go back to Egypt. God told Abraham to sacrifice his son, Isaac. It was a test of Abraham's devotion to God and not a desire to see blood spilled. Christian theology often sees this as foreshadowing the Crucifixation.
Regarding slavery: you're going to make me find my history books and Cliff's Notes for the Old Testament, aren't you? | 
