Yep. The 50% faster frame rate
I see a lot of "up to" 6 fps, not just 6 fps, so I wonder what the weasel words are hiding. I also read that auto-AF-select is even slower and less useful than the 5D2's.
better sealing
I'm sure that both people shoot from inside waterfalls appreciate that.
better viewfinder
How is not being able to see what AF spot is selected "better"??
dual card slots
One CF slot.
shutter lag reduced by half
Welcome, but not along worth rebuying a body.
better metering
Pretty much everything has better metering than the 5D2. Having to routinely shoot with EC +1 is an embarrassment.
better ergonomics
Vaguebook much?
including a multicontroller on the grip
The pictures I find of the 5D3 show no such thing. It'd be really awkward to hold if it did.
it does seem like Canon ignored everything but the AF. Right.
The sensor is effectively identical to that in the 5D2, no high-ISO usability improvement, no improvement on low-ISO banding/shadow noise. Note that having more aggressive default NR when saving to JPEG files does not qualify as a high-ISO improvement.