Couldn’t God, being almighty, have chosen a faster way to reconcile man with himself?
God could certainly have chosen any method he wanted to save us. God chose the Passion because it showed the depravity of sin and the depths of his love.
Thomas Aquinas (Summa III Q46 A3) noted that while anything God chose would have sufficed for our salvation, the Passion was the perfect means because:
The saving Passion of Christ is the great mystery of faith. At Mass when the priest celebrant intones “The mystery of faith” after the consecration of the chalice, he is referring to the Eucharistic sacrifice that has just been made present in our midst.