Thinking on this a little further, I suspect another reason that they're dropping the "deep truths" one after another is that they're probably going to try to emulate the mormons in yet another way - the "testimony." As I understand it, the end of the book of mormon basically says to pray to god for confirmation that the things in the book are true. This essentially plays into an aspect of the human psyche, in which you don't want to believe that you've just wasted all that time reading a stupid worthless book, so your mind plays a trick on you and you become convinced that you've recieved a direct message from god that the book of mormon is the true word of god. A similar tactic was used in the heaven's gate recruitment videos - he told people to go into a closet and pray for a revelation to determine if what he said was true.
I think this is the direction they're heading. They'll put something in the end of the books that are to be studied with people (and in bookstudy) that says that we should all pray to god and ask him if the religion is true (probably with some out-of-context scriptural citation that no one will read). It will work for essentially 100% of JWs, because even if they don't feel that they've recieved the personal testimony from god, they'll have to say that they did. If they say it enough, they'll start to believe it.
This will be a much more powerful hold on the members. Currently, there are still many members (mostly older ones) that feel that the "truth" can be proven. This is dangerous because it gives an opening for the truth to be disproven to them, which is easier now than it's ever been, thanks to the internet. Once they go the personal testimony route of the mormons, no one will ever be able to disprove it. Any attack on the cult will be an attack on a personal religious experience.