The Mosaic Law was only the external show of that pre-existing law of death and condemnation as shown in Adam.  Its passing in history was given to signify the passing from death to life in Christ.  To focus solely on the Mosaic institutions themselves as the focus of "the law" is to miss its schoolmaster role.

• The Passing of the Law in History showing  in Christ - Externally Done Away in the Past FOR ALL.. or Internally Done Away in Christ FOR SOME :

COMMENTS FROM MODERN IDEALISTS

Marcus Booker
"Preterists maintain is that death has already been destroyed, the victory already won. Maybe so! Indeed, maybe so on a visible historical scale in reference to the Mosaic economy and the Temple of Herod. Yet maybe not so quite yet with reference to the individual."  (When Our House is Torn Down)

Todd Dennis
"Really, the one big mistake Christianity has made in regards to its exegetical maturation has been that it has taken the natural and historicizing methods of Old Testament interpretation and transferred them to the New. This is why there are so many fruitless debates over what historical aspect is the true fullness of revelation. For instance, consider these questions, while paying attention to the fundamental historicity of BOTH propositions:

-Was the Sabbath changed from Saturday to Sunday?
-Was the Kingdom transferred from Israel to the Church?
-Was the Passover transferred to the Lord's Supper?
-Was the Exodus fulfilled when Jesus came out of Egypt as a boy?
-Did the Old Heavens and Earth become the New in the 1st Century?

The problem with this type of dialogue is that -- and pay attention to this point, because it is the guiding interpretive principle of this entire blog -- God's revelation does not go from natural to natural... but from natural to spiritual. Therefore, instead of looking "horizontally" to the future for the substance of revelation, we are meant to look "vertically" and see how all biblical models are fulfilled in Jesus Christ alone. Therefore, the Idealist point of view would suggest looking at the same controversies like this:

-Jewish Sabbath only stood as a shadow of Everlasting Rest in Christ. (Heb 4:10)
-Jewish Kingdom was always the picture of Everlasting Kingdom of Jesus. (John 18:36)
-Passover always looked to our partaking of Lord's Self Sacrifice. (1 Peter 4:13)
-"Exodus" in the Bible points to deliverance from sin for Lord's children. (Heb. 3:10-13)
-Old Heavens and Earth only become new in Jesus Christ (II Cor. 5:17)"

Scott Thompson
“But now apart from the Law the righteousness of God has been manifested, being witnessed by the Law and the Prophets, even the righteousness of God through faith in Jesus Christ for all those who believe” (Romans 3:21-22). The reason God does it that way is because it is impossible for sinners to save themselves, “for there is no distinction, for all have sinned and fall short of the glory of God, being justified as a gift by His grace through the redemption which is in Christ Jesus” (vv. 23-24).

The word “Law” in this passage embraces all human effort to attain a right relationship with God. The Bible clearly teaches that God’s righteousness is received as a gift apart from any human effort. We do not contribute anything in any manner to our justification. All our human efforts bring upon us the judgment of God.

What God began in you by His grace He will finish (Phi. 1:6). He will see your salvation through to completion. He has a great investment in you and He will not lose it." (Righteousness Apart from the Law)

COMMENTS FROM INCIDENTAL IDEALISTS

Thomas Hartwell Horne (1852)
It evidently appears, from comparing the history and economy of Moses with the whole of the New Testament, that the ritual law was typical of the Messiah and of Gospel blessings ; and this point has been so clearly established by the great apostle of the Gentiles in his Epistle to the Hebrews, that it will suffice to adduce a very few examples, to show the nature of Legal Types. Thus«, the entire constitution, and offerings of the Levitical priesthood, typically prefigured Christ the great high-priest (Heb. v. vii. viii.) " (An Introduction to the Critical Study and Knowledge of the Holy Scriptures, P. 385)