Harold B. Lee says that the endowment's message has always been the same.
Harold B. Lee, Genealogical Devotional Address, BYU, August 16, 1968, in Clyde J. Williams ed., The Teachings of Harold B. Lee (Salt Lake City: Bookcraft 1996), 578, 653
The same message has always been given in the temple. Now, you think for a moment-in the upper office over [Joseph Smith's] store, with no equipment like we have in our temples today, the endowment had to be given by lecture. The Prophet Joseph Smith, through these his counselors and others as you heard their names, attended to the matters that we now have given in various ways. Sometimes our people who go through the temples are a bit startled because of the varied ways in which the endowment is presented. Perhaps, as under inspiration they studied the nature of the endowment, they thought to make it a little more meaningful to the patrons who would come: part by dramatization, part by question and answer, party by lecture, part by picturization on the wall of some of the temples. We have artists who have tried to put those who go through the temple in the mood of the lesson to be taught as they proceed through the temple.
In our more recent times, as the many language problems presented themselves (like those in the Swiss Temple, where we may have a German-speaking session today, a French-speaking tomorrow, and an English-speaking the next day, as well as Scandinavian sessions), by picturing the endowment on a screen rather than by giving it by lecture and dramatization, the same message can be given with a minimum number of workers like we have in other temples. But its the same message that was given by lecture by the Prophet Joseph Smith in his officer over the John Taylor store. Now, when we have that in mind, we will see why the Prophet, in the beginning of this dispensation, gave certain instructions to have the brethren stimulated in their thinking.