D800 Live View Problem?
I got rid of my D800 because of this very reason.
I shoot 100% landscapes on a professional level, so the D800 sensor was pretty sweet on paper. I'm also 6'4" tall and do a lot of low angle photography where it hurts too much to use the viewfinder for more than a few seconds. I also don't like laying down in mud and other crap.
Live view helps me tremendously to get shots I would otherwise pass on.
I had to get rid of the D800 because of the very high levels of noise in the LV screen even at indoor lighting levels with a 60 watt lamp, along with the funky line skipping aliasing when trying to manual focus at full zoom.
I went with a Canon 6D instead and the Live View is about as good as it gets in a DSLR. Even with a 10 stop filter on the camera, I can focus and compose using Live View. It was way more than enough to not make me mind the lesser dynamic range and resolution. I exposure bracket and stitch all the time, so those things really don't make as much of a difference as I would have thought. The 6D has 2 shot bracketing, which is great for instances when 3 shot bracketing is overkill and wastes memory and time. Factor in that I can also stream live view to my iPhone, and the 6D has quite an advantage when the viewfinder and screen are impossible/difficult to see.
I wonder if the Sony A7R 36MP sensor has solved the Live View issues?