I think we do a grave disservice to members by our refusal to talk about the temple much more openly.
Seriously, just about everything is available to the public now - and most of it has been explained in "faithful" writings. On top of that, there really isn't very much that is forbidden to be discussed in the actual temple wording. When you listen really carefully and don't credit all the things that individual members say, the only things that are forbidden specifically deal with one very narrow aspect - and I understand not talking about that aspect.
There is NOTHING that forbids me from explaining the entire endowment to my children - or anyone else - in great detail, as long as I am careful not to cross the line I mentioned above. I can explain that it is a play or movie, depending on the location - a presentation of the creation of the universe - of the creation of humans (figuratively) - of the conflict between following God or Lucifer - of the introduction of religion and the need to search for people who speak for Heavenly Father - of the things we need to accept and try to do in order to become like God - of our admission into the presence of God. I can explain that I view it almost all as symbolic - and why. I can talk about the covenants and how I interpret them. etc., etc., etc.
I can go into lots of detail - and I believe strongly that our Temple Prep classes should do so. There is NO solid reason that anyone should go to the temple for the first time and be surprised in any way - and I believe that deeply and passionately. It is one of our greatest failures in the Church, in my opinion - and it is completely unnecessary, given what actually is said in the temple itself.