Some very interesting stuff there, and thanks for taking the time to outline your thoughts.
I would agree that one clear difficulty is maintaining an authoritative style when so many of the authors with real experience and knowledge have gone. Naturally, even with the best will in the world it is impossible to add anything to existing information, unless one happens to have been personally involved with the subjects that are being described. I guess it's a problem that is likely to get worse, not better.
I wonder if anyone has any thoughts on the "Aeroplane Icons" series too? The most recent issues have covered TSR2, Vulcan and Spitfire. It would be vey interesting to hear what readers (or potential readers) think of them (good or bad points!)...