Unless you are printing really BIG, those megapixels are not adding much to the average 16x24 print. At 32x48, viewed from the right distance, you might see a minor difference. Today's software for printing is really what gets the pixels onto the paper.
For instance, the D600/D7100 have a native print resolution @240dpi of 25 inches on the long side. I pick 240 instead of 300 for a reason - I use Epson printers. As it turns out the driver for any of the large Epson K3 printers takes that native 240dpi and uprez's to 1440dpi for the inkjet head spray pattern. It is going to do the exact same thing for the D800 so there goes the resolution advantage at smaller print sizes and most people don't think of 16x24 as small.
>Yes, the D800 needs a well practiced technique,
I have to disagree somewhat with this statement and I have seen it come up in forums each time Nikon has bumped megapixels in their cameras. The D800 requires no more proper technique than any other camera. Let me emphasize the word, "proper".
From my own experience, I have found NO difference in shooting either film or digital, regardless of resolution. One either has technique for the type of shooting one is doing or not. Megapixels are not the challenge, practice and understanding of equipment and photography are.
Finally, to more directly address what I perceived the OP was asking about at the beginning of this thread, having shot both of these FX cameras enough to having more than passing familiarity with the D800, it is not the ideal wildlife camera for someone that cannot afford ~$6k-$10k Nikkor telephoto primes with Nikkor teleconverters and I see from your profile that you have the where-with-all to purchase such lenses. But if you go back to my earlier response, the D7100 will consistently put more pixels on wildlife-like objects than the D800 at any focal length. To me, it is the new, ideal cost/value landscape and wildlife camera and I am seriously considering it as a companion to my D600.
Your mileage may vary.
"Extraordinary claims require extraordinary proof " - Carl Sagan