As I have been reading the changes in the 1990 endowment, I see that many of the changes are concessions to feminism.
For instance, instead of Eve (and the LDS women in attendance) promising to obey “the law of their husbands”, they now promise to obey “the law of the Lord”.
Also completely deleted is the part where Elohim (the Mormon god the father) tells Eve:
Eve, because thou hast hearkened to the voice of Satan and hast partaken of the forbidden fruit, and given unto Adam, I will greatly multiply thy sorrow and thy conception; in sorrow shalt thou bring forth children. Nevertheless, thou mayest be preserved in child-bearing. Thy desire shall be to thy husband, and he shall rule over thee in righteousness.
(Italics mine) I thought it was strange that they took this out, because it (unlike the rest of the endowment) is in the bible (Genesis chapter 3).
The other big thing that has been deleted are the masonic penalties for revealing the secret masonic handshakes and passwords. No more throat-sltting and disembowlment. Originally, the penalties were seen as inseparable from the signs and tokens.
Since Mormons never discuss the endowment outside of the temple, those who began temple attendance after 1990 will likely never know that these elements of the ceremony ever existed.