Since my D800 arrived towards the end of March, I have made around 3500 exposures (I am strictly an amateur hobbyist, you understand), including 2800 on a 7-week vacation taking in half a dozen National Parks in western USA. So I have done a lot of landscapes.
I don't normally print larger than A3+ but I do sometimes make that size of print from very tight crops (maybe only 10% of the total image area at times).
Like you, I had read all the scare stories on here and elsewhere but I have to say that I have personally found no problems at all. The images are certainly far sharper, with a range of good lenses, than anything I could produce in similar circumstances with the D3s I replaced with the D800 or the D700 before that. Naturally I use Aperture Priority or, more often, Manual for landscapes and, by a large margin, my most commonly used aperture is f/11. No problems at all at that aperture. Possibly haven't used f/16 - f/22 enough to comment meaningfully.