When we became followers of Jesus, why didn't God perfect us? Why not transform us into morally perfect beings? Imagine the tremendous testimony.
Part of the answer is: going through the sanctification process is not just about becoming like Jesus. It is also about learning about God, people, relationship and forgiveness.
God also created many cultures. Why? God has placed a small piece of Himself in every culture. As we express this piece of God in our culture, we demonstrate God's nature to the world. And, as we see the faithful of God in China, India, Kenya and Kazakhstan express that piece of God from their culture, we see God in new ways. We learn what God values from His heart being expressed in and through them.
Many cultures have well-defined expressions of community. We learn God's heart about unity, mutual care giving, mutual encouragement and the need for all of us to have a place.
I have heard American praise these cultures amd lament living in America. As if God was displeased with America and its culture. As if God was somehow surprised by the way America turned out. What do we see when we look at America with God's eyes? We see how God values personal initiative, creativity, responsibility, risk taking, hard work, diversity, as well as individuals and minorities.
(There are not too many places in the world, where one person can stand in front of the whole nation and say "You're wrong!" and be right.)