Historically, the works of Enoch have always been considered an elaboration on the Torah, but what if this is backwards, and in fact the Torah is a revision of Enoch?!
The Wikipedia page on Enoch notes:
the idea of the origin of the evil caused by the fallen angels, who came on the earth to unite with human women. These fallen angels are considered ultimately responsible for the spread of evil and impurity on the earth;
the absence in 1 Enoch of formal parallels to the specific laws and commandments found in the Mosaic Torah and of references to issues like Shabbat observance or the rite of circumcision. The Sinaitic covenant and Torah are not of central importance in the Book of Enoch;
the concept of "End of Days" as the time of final judgment that takes the place of promised earthly rewards;
the rejection of the Second Temple's sacrifices considered impure: according to Enoch 89:73, the Jews, when returned from the exile, "reared up that tower (the temple) and they began again to place a table before the tower, but all the bread on it was polluted and not pure";
the presentation of heaven in 1 Enoch 1-36, not in terms of the Jerusalem temple and its priests, but modelling God and his angels on an ancient near eastern or Hellenistic court, with its king and courtiers;
a solar calendar in opposition to the lunar calendar used in the Second Temple (a very important aspect for the determination of the dates of religious feasts);
an interest in the angelic world that involves life after death.
The works of Enoch make no mention of the Torah or Moses.
However, Books 3 and 4 do place importance on the number 12, primarily in association with the solar calendar. However there is no mention of 12 tribes.
Opposition to the Temple could easily go right back to the Persian era, with Judahites who opposed what they saw as a Persian-backed system of control, which is what Enoch 89:73 implies.
Many works of the prophets also make no mention of Moses or Twelve Tribes or the Ten Commandments. Could it be that such works of the prophets are the common works shared between the writers of Enoch and the Torah, and that the Enoch group was opposed to the Persian-backed priesthood. The writers of the Torah are descended from the Persian-backed priesthood who controlled the Temple. When they wrote the Torah, they used lore that is found in Enoch. This could either be because Enoch was already written, or it could be that both the writers of the Torah and Enoch were both simply drawing upon common Semitic lore. Either way, the writers of the Torah developed narratives that intentionally contradicted the lore we find in Enoch. Thus, the attribution of sin and corruption of the earth to the actions of people in Genesis was a direct retort to the lore found in Enoch that attributes sin and corruption to heavenly powers.
The Temple priesthood would have done this because they saw other heavenly powers as potential rivals to God who could be construed as other gods. If you are powerful enough to corrupt the world, then you are a rival god. So they, in making clear that there were no rival powers to God, had to attribute sin and corruption to God's creation, humans themselves. This setup the split that ultimately gave rise to Gnosticism, with strains Jews not accepting the Temple priesthood and its teachings that placed blame for the corruption of the world on humans instead of heavenly powers.
?? Speculation...