>>7anti-sex and anti-science
The only precept about sex is "Don´t hurt others with your sexuality" or something like that.
About science, I don´t think so; the actual lama even said that they will change their beliefs if science finds out they were wrong.
invented ridiculously complicated, and mostly useless, systems of philosophy
I agree.
The problem with knowledge based on spiritual and mystical experiences is that it will sound weird if you try to translate it to words or logical systems. That´s why we always find a lot of strange supertition to explain it all.
I think a good solution is to speak with metaphors, analogies, etc, so you are not really describing (degrading) the knowledge, but guiding people to get to the same experiences you got.