tr;dr 1. The lens focal length matters more in practice. 2. There won't be more blur detectable when looking at a full-screen image, but since the D800 can resolve finer detail, it can also resolve smaller motion blur (if you're pixel peeping).
If you are talking about the difficulty of having no motion blur visible at the pixel level (not full image), then yes, it is more difficult. But how much more difficult? The D800 have 1.5 times more pixels horizontally in the image than the D7000. This means that with the D7000 you can get away with a 1.5 bigger turn of the camera during the exposure before the shake will become detectable.
But how much does the camera need to turn during shaking to have a motion blur of more than 1 pixel? That depends on the focal length of the lens, of course. Longer lenses are more difficult to shoot with hand-held because they magnify angular motion more.
So to put the difference between these cameras into a different perspective, to have all pixels sharp, the slowest usable shutter speed with an 50 mm equivalent lens on the D800 would be the same as the slowest usable shutter speed with a 75 mm equivalent lens on a D7000.
That said, as others noted: the reason why the D800 can reveal motion blur more easily is because it can resolve finer detail. I.e. you can zoom in more, until you see that tiny motion blur. If you look at the complete image, there won't be any more motion blur visible from the D800. In other words, in practice this is a non-issue.