a. Expiation is Christ's appeasing the Father's wrath against sin and sinners, securing pardon or condoning sin. At best it is overcoming sin on lower levels, only to have it reappear on higher levels.
b. In some mysterious way there is an expiation for sin that satisfies God's wrath against sinners. Who else could the expiation satisfy? Overemphasis of legalistic framework of atonement eclipses power of grace.
c. Although God truly hates sin, the sacrifice of Christ did not "appease" Him or motivate Him to love sinners, for He already loved them. The propitiation is given by the Father; it reconciles the believing sinner and the universe. As flesh clothes bones, so grace clothes the legal basis of the atonement.