When Christians die, heaven does not “get another angel.” We cannot become angels any more than we can become giraffes or ocean waves or stars. We are people and will remain so after this present life. God did not make a mistake when he made us human.
When talking about God’s ultimate destination for us, we’ve grown sloppy in our language, nearsighted in our gaze, and un-Easter in our hope. We act and speak as if dying and going to heaven is what the faith is all about. It is most emphatically not.
The main point Paul has been getting at in Romans is what God has done in the One man Jesus the Messiah—the rightful heir of God’s earthly kingdom—is far, far more than simply putting the human race back where it was before the intrusion of sin.