The H2P section. It's mostly talents and glyphs that are lilsted there. And if you look at most boss threads it has not even more than a single page of replies. That's over the course of like 1 year? How is that significant?
The Mind Sear and Mind Flay thread is a matter of how you define how to improve. I'd say that thread is more theorycraft than actual gameplay and how you improve at it.
All the threads you mentioned I have read when they were released. My point was that not many people are interested and it's clearly seen in those threads. I'm not denying that there are people out there who would find those videos useful but I don't see the time invested as worth it unless you're bored. The frequency of responses to the threads you linked and the lack of discussion in those threads proves my point.