In response to examples of the d800's moire, Gizmodo's side by side tests of the d800 and 5d3 showed an incredible amount of moire in the daytime shot of a skyline. The camera is panning to the right and as it gets to the right there is a building that is being absolutely devastated by moire. I found this a pretty telling thing because the building hardly even looked like something that should have caused moire in the first place. It certainly wasn't a brick wall of fine details is what I'm saying.
In all honesty though, aliasing is my biggest concern. In the entire feature film I shot on the 5d2, only 2 shots display any moire (using only sharp Zeiss wide angles and a singh-ray variable ND)... But nearly all shots display some amount of aliasing. This is what was great about Phillip Bloom's review of the 5d3, while the nature wasn't the best example for moire, it's a wonderful example to show aliasing. It is practically non-existent on the 5d3. While the d800 is out resolving the 5d3, the aliasing does not look promising. Though maybe the samples have in-camera sharpening applied.
Aliasing (and moire when it exists) is the final thing affecting the filmic look of DSLR footage. You can shoot 24fps with almost the correct shutter speed of 48, and you can apply a beautiful filmic color correction in post, but nothing will make your footage look like true film if jagged digital edges are present.
You can definitely argue that resolution is another thing holding back a real film look, but I don't think the d800 is the answer there... Maybe once a third-party anti-aliasing filter is tested. Personally, because of my Canon glass, I'd probably rent a C300 for a higher budget shoot. For something with the sub 10k budget of my last film, I'm sticking with my 5d3.
Take everything I say with a grain of salt though, as I am a photographer first and the 5d3 is my perfect camera for photography. I do believe though that that is something that can set you apart. I approach cinema no different than my regular photography and it can make for something more unique than the traditional master, closeup, closeup of normal shoots. We filmed about 1/4 of our movie The Battery in static single shots with no coverage, but it fit the lonely feeling we were going for. I know I can't compete with the big boys in cinematography, so I want to do something different.