1) Nikon D800 is better than the 5D3 in almost all aspects, even video.
2) Very overpriced Canon Cinema division got destroyed at NAB by Black Magic and Sony who stole all the buzz.
3) Now Tamron fills the I.S. niche that #1 feature in the 24-70 that Canon customers were begging and pleading for, but Canon failed to deliver.
1) That's an opinion, there are plenty of people that prefer the 5DIII.
2) The Black Magic camera is very cool, but geared more towards consumers. The Cinema EOS cameras are for the film industry. See how many Hollywood productions end up using the BM camera, I'm sure it won't be many. 2.4x crop is a joke (I know it's useful in some applications, but obviously you can't shoot everything on it).
3) I'll agree with you on this one, but the 24-70 II really hasn't been tested yet. I don't think IS is very essential in that range. You'd think that no one had ever taken a good picture with a 28-70 or the current 24-70 the way some people cry about IS, people have done just fine without it.
You say "non-Canon fanboys" prefer the D800, which is pretty much saying "Nikon fanboys prefer the D800." You can claim these products as failures all you want, but I guarantee you all of them will sell well within their respective markets. The 5DIII has been selling like crazy, if it was that bad of a camera no one would buy it. The D800 is a great camera, but the MP count makes it seem better than it really is.