Having had one, its a fine camera, but, as noted, even with high end Nikon Glass, its is difficult to get the resolution that the body can provide.
Let's suppose one buys a D800 and a few lenses capable of exploiting its resolution. When you and others refer to difficulty (presumably this involves the need for a tripod, mirror lock-up, etc., and attendant skills) of realizing the camera's potential, are you saying that someone who chooses for whatever reason to use it hand-held will, other things being equal, get photos that are worse, or at least no better, than if he had used a D600 or D700 or 5DII/III or 6D etc., or that they will still look better, but not as good as they could?
Back when DPR first tested it using the 50mm Nikon lens, they had and mentioned that they found it took extreme care to get the sharpest images, even with their studio setup and heavy duty tripod, it was difficult to consistently get the resolution they expected. After buying mine to use with a 24-70mmG, I concur, its difficult but not impossible. For landscape photographers who are accustomed to spending long periods waiting for the perfect image, this is not a big deal.
Using similar care, you certainly won't get worse resolution than 5D MK III or similar, so thats not a issue unless you expected to get higher resolution. You will get excellent DR, even with a lesser lens.
The Huge raw files, and they really get big when you set a high ISO are slow to process unless you also get the latest computer with SSD's. I just upgraded from a first version intel i7 to the latest with fast SSD's, a ton of memory, and they now process in a reasonable amount of time.
Many users don't want to drop 2K or more on a new computer when they have one three years old that seems fine.