D600/D800 high-ISO video: is it really this bad?

Just when I thought I'd decided on the €1600 D600 (what a price that is!), I get stopped in my tracks by awful-looking high-ISO video samples. Awful is relative to the 5DIII, of course (which is €1000 more than the D600, and €500 more than the D800).

Here are just two examples I found online, but others confirm the horrible flickering blue-noise in dark areas of the Nikon's image when ISO is pushed beyond the native comfort zone:

https://www.youtube.com/watch?v=K8KIBrCvxy0

https://www.youtube.com/watch?v=lIKcfKhE-ew

As I often shoot videos using the maximum ISO-12800 of my 5DII it does seem the Nikons are out after all, here's a video I shot the other week, you can see how useful the superior 5DIII's video would be for me:

https://www.youtube.com/watch?v=-JX-Wa7fqPY

One question still, if you set the D600/800's to maximum and shoot ISO-25600 (hi-2) video, does the filter get rid of that blue-noise flickering? I guess another method would be to shoot at 25600 using the uncompressed mode, then setting a powerful NR filter on the file in post (which would probably take a week to process, haha).

It's a shame, really...as there's otherwise so much good camera in the Nikons, especially for stills (more DR, better resolution). But I think I may have just found the one big obvious reason to help me choose.