Tom, I admire your tenacity (though its now become a long term thing) and its good to see you stimulating our gray matter.
The timeless and universal purpose of the law:
1 Timothy 1:9 Knowing this, that the law is not made for a righteous man, but for the lawless and disobedient, for the ungodly and for sinners, for unholy and profane, for murderers of fathers and murderers of mothers, for manslayers.
This will stand while there is still sinful flesh to be controlled and/or punished working as a tool by the Spirit (either by letter or written upon the heart via the conscience) to reprove/convict men of sin.
God's work of regeneration does not and will not eradicate the flesh upon regeneration but provides the power to overcome it (to have dominion over it). The flesh necessitates the law.
Preterism's difficulty:
Preterism has no explanation for the present day existence of the flesh, and sin and death and thereby diminishes the power of Christ:
Neither can it tell us how long all this sin and death will remain in this material universe or how this material universe will end seeing that all has been fulfilled in the preterist point of view. Sin yet reigning over this world.
1 John 3:8 He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.
There is one who is coming who will conquer, cleanse and purify the universe in its entirety:
Act 1
3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:
4 And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me.
5 For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
6 When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel?
7 And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power.
8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.
9 And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight.
10 And while they looked stedfastly toward heaven as he went up, behold, two men stood by them in white apparel;
11 Which also said, Ye men of Galilee, why stand ye gazing up into heaven? this same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen him go into heaven.
We have not seen this same Jesus (not Titus) return in like manner (bodily form) as He was seen to leave, but when He does He will assuredly put an end to this miserable abode of sin and death and then and only then will the law become an unecessary tool of the Spirit of God.
HankD