I also think the 5D3 will be great for landscapes, and also lower light indoor shots without using a flash, which can often be a problem when taking shots of larger groups indoors at night.
The higher FPS also means it will be quite OK for sports, so IMHO, I think the 5D3 will be a great all-aroud camera for the more serious photographer - and that's me to a tee!
22mp is more than enough.
Many years ago, I had a D60 (which I still have actually and I'm thinking of getting it changed into an infra-red camera) and it's paltry few mp still gave reasonable shots, at low ISO's, and my new 60D is good, but the high ISO is not so good, so for me, the 5D3 seems perfect.
I do have a grip fo rmy 60D, but I often don't want to lug it around with me, so 1Dx wouldn't suit me, so the 5D3 seems to be the perfect halfway house.
I'm also dieing to try my new Sigma 150mm macro with OS on the 5D3!
The results should be spectacular.