Consequently, in straight language, obviously it fails.
Except that it doesn't work. Other than that it's "perfect".
Redemption is simple - Jesus was the perfect SIN OFFERING and we, as gifted by God, are redeemed by FAITH in That offering (gifted to us by God EPh 2:8,9).
What more do you need to know??
Chuckle!!! "MY imperfect method" vs Your "almost universally established ( but equally as imperfect) method".
Jesus said that the HOLY SPIRIT (not man's "Theology") would lead us into truth, and give wisdom freely as long as we seek Him singlemindedly. I tend to think that's TRUE.
So which "Perfect/imperfect" systematic do YOU trust to tell you the truth???
Redemption incorporates a great deal more than your simplistic summary (e.g. it involves us being purchased from the slave-market of sin, our ownership being transferred from Satan to Jesus; it involves the payment of a price to purchase us, that payment being made to God, not Satan; then there is the picture of the kinsman-redeemer, in the OT, with its accompanying doctrines, etc, etc.)! We should know about it all, otherwise the LORD would not have bothered to tell us.
Yes, the Holy Spirit leads us into all truth; but, he does not do it through presumption and indolence!
1) Look up all places in the Bible that deal with the subject at hand.
2) Starting with the earliest one, which usually gives the foundational meaning, check the meanings of important words, in the Hebrew and Greek; check the grammar and the immediate context and find out the author, including any known quirks, as well as the intended audience, which can often provide insight into the correct interpretation.
3) Take note of what is taught and how that teaching progresses, throughout the Bible.
4) Interpret any tricky or obscure passages by the clear, simple ones.
5) Make sure that your interpretations do not contradict any other scriptures.
6) Check to see if there are differences between the concepts, as taught in the Old and New Covenants (there often are).
7) Check reputable commentaries, to see if the authors have insights that you might have missed.
8) Do all this prayerfully and diligently. Whatever your hand finds to do, do it with your might, as to the Lord and not to men.
The above is a summary (there are other points that could be included), but it is a good starting point. Many Web sites and books will have more detailed explanations.