Personally a bit disappointed that the ST reference books we're getting now all seem to be aimed at children/younger readers (i.e. thios book and the recent Enterprise tour book by Okuda). They just don't do anything for me, but I'm happy that the younger Trek fans have them.
Miss the technical manuals, and episode guides and such. And before someone posts it: I do realize the reasons why we don't see those anymore, and why we probably won't anytime soon.
I'm not sure that's an accurate assessment of the current output. There's been a huge resurgence in Star Trek non-fiction in recent years, including the introductory/younger audience books you cite, light hearted interpretations, a couple of craft books coming up, and plenty of more in-depth titles for grown-ups/experienced trekkies: In the past few months alone we've had a the Klingon Bird of Prey Haynes Manual, which goes into a great deal of technical detail. Federation: The First 150 Years, with two centuries of Star Trek history, and the TNG 365 with all sorts of production information.