Landscape photographers in particular, who have a tendency to print huge, can always use more megapixels. Sadly, Landscape photographers also consume dynamic range like it was candy, so if Canon's 46.1mp camera doesn't have competitive DR, the better options for landscape photographers would still be the D800. I seriously hope Canon resolves their DR issues with the new 46mp sensor.
Not all landscape photographers have a tendency to print large.
LOL. Ah, good laugh man.
It's just a "tendency". Tendency does not imply all landscape photographers everywhere do, just that there is a higher likelyhood of landscape photographers, at least those who are in business and selling their prints, to print larger.
Most will not have the customer base to sell such large prints and certainly won't have the ability to print that large without outsourcing at significant additional cost. Also, DR isn't necessarily important for landscape photographers, it may be useful, but most professional or advanced landscape photographers would be using grad filters, which would make higher DR less important to them. Also, increased DR could also reduce the impact of images, as the most important feature of memorable landscape photographs is a full tonal range, including shadows, not to mention composition. There are a number of successful landscape photographers who have used relatively low end cameras and there are even more who have come from a film background who either don't know or don't care about the technology and just use the equipment that gets the job done.
It is the photographer who is the most important part of photography and I hope always will be. Yes, equipment may limit the photographer, but in reality it is rare that it is more limiting than ability, creativity and imagination, especially for subjects that don't really move. It is far more likely that a sports or wildlife photographer will be limited by their equipment than a landscape or traditional portrait photographer (i.e. the typical studio portrait), otherwise the only limits are themselves.
You are misunderstanding the value of improved dynamic range for a landscape photographer. I own the Lee Filters filter system myself, and own quite a number of lee GND filters, ND filters, etc. The use of a graduated neutral density filter is COMPENSATION for NOT having more dynamic range in our cameras. In some scenes, you just plain and simply MUST, because the scene itself might contain 20 stops or so of dynamic range. But in a lot of situations, if you could actually use all 14 stops of DR modern DSLRs have, you would need to haul out the GND's less frequently, or use less dense ones. I like the power of having GND filters in my kit, but they are not the ideal solution like having more DR is...they have issues...such as darkening the tips of mountaintops, the tops of tall trees, etc....sometimes darkening them so much they come out nearly solid black. I've never liked that about GND filters.
I'd also point out that "having" more dynamic range does not mean your final image "uses" all that dynamic range. The entire point is to be able to push around your exposure in post. Dynamic range improves your active real-world photographic editing capabilities in post. No screen currently on the market, even the top of the line $8000 TV's with adaptive dithering algorithms that can "display" 12 bits of color depth on a 10-bit display, can show the kind of dynamic range we are technically capable of capturing today (with a camera like the D800 anyway). Displaying it all at once isn't the point. You still want to compress it into the smaller 8 stops of the average computer screen, or the 5-7 stops of the average print, and you want it to have that "pop" and saturation that a good landscape photograph does. With more DR, it just means that your deep blacks will have useful detail...rather than just noise (and better yet, in a camera with low read noise, your deep blacks won't have any nasty pattern or banding noise.)
What you print will probably only have 6 stops, but having the full 14 stops of dynamic range to work with initially is the entire point...you can maximize the potential of those final 6 stops.