>So, am I losing focus because of the high resolution? This >never occureded to me.
Not exactly. It's likely that focus is soft because your shutter speed is too slow. The more megapixels that are used to record and given subject, the greater the likelihood that tiny amounts of movement will be recorded by the sensor. Increasing shutter speed reduces the effects of those tiny movements (heart pumping, slight hand movements, slight body shift, slight movement when the shutter is pressed, and so on).
It's possible for me, personally, to grab a series of consistently razor sharp, handheld shots of a static object at 100mm, VR on, 1/60s with my D700. For me, personally, to be able to grab the exact same series of shots of the given object with my D800 with the same lens at 100mm, VR on, handheld, I personally need a shutter speed of at least 1/160s.
That's a huge difference, and a very graphic demonstration of how much more and finer detail the D800 can capture as long as I'm using a shutter speed equal to the task. High resolution doesn't equal soft focus. High resolution + inappropriately slow shutter equals soft focus when shooting handheld.
Note too that even a tripod setup for the D800 must respect the effects of very slight movement of the rig caused by wind, footfalls, slightly unstable positioning, dangling camera strap, and so on. Higher resolutions come with a penalty, which is basically that several aspects of shooting technique have to be addressed to take full advantage of the high resolution.
Best analogy I can come up with is this. Everybody can drive a Volkswagen Jetta. It's a perfectly good car. I own the TDI clean diesel version. Love it. Millions of people drive the things safely and well. Put those same people behind the wheel of a Corvette though and an enormous percentage of them will be fishtailing, squealing the tires, having trouble with braking, struggling with peripheral visibility, oversteering because of the rapid ratio/response of the wheel, and be really uncomfortable with their low driving position. They'll have to adjust their driving techniques and practices quite significantly in order to get safe control of the vehicle. There's nothing wrong with the hot car (or the hot camera), but the drivers' and photographers' practices and techniques need to improve in respect of the greater power and precision of the vehicle and in respect of the greater power and resolution of the camera.