I MUST be doing something wrong

I didn't have any problems untill D7000. At this point, after a good deal of trying and tweaking, I've figured out some of its quirks, and with much lens fine-tuning, extra careful AF-mode selection, metering selection, exposure compensation, and picture control selection, plus (probably) a somewhat improved shooting technique, I get decent results when (rarely) I do choose to use it.

So, what does this tell me about D800 complaints, -- that in many cases one likely can work around all of these so called issues and find some optimal settings for the D800 too (I don't doubt the existence of many defective units though), but I don't have a D800 myself, so this is a speculative statement.

However, from the point of view of usability of the newer Nikons, I would say one thing pretty much unequivocally -- the usability is not what it should be. If a lot of experienced photographers who never had any issues with all the previous models you listed, suddenly have to jump through the hoops to find the sweet spot of the new cameras, then I think something is wrong. The mark of good usability is being intuitive. Many changes Nikon introduced have made it less intuitive to get the results one expects. If this happens to a lot of folks with many years of previous Nikon experience, -- then something is not right.

The only other conjecture is that the internet forums suddenly became much more popular with disaffected folks, because where were all those complainers with D300 and D700 for instance?