I only want two things in the 7D2. Less noise at higher ISO -- ideally a 2 stop boost. And a locking mode dial. More AF points and higher FPS would be nice pluses, but not necessary for me.
The one feature that intrigues me about the 5D3 is it's performance in low light. Based on researching online reviews, I estimate the benefit to be about 3 stops over the 7D (and my 60D). So, I've dreamed about swapping my 60D/17-55 2.8 IS for the 5DIII/24-105 4L IS -- a logical upgrade path.
I would be losing a stop on the lens for a net gain of 2 stops in low light performance.
Now, if the 7D2 offered that 2 stop boost, I wouldn't need the 5D3 -- which is why I fear that the 7D2 will only have a modest boost in low light performance. Granted, the 5D3 offers sharper images and deeper color, but I suspect its low light advantage is a key reason that many consider it to be the logical upgrade for a 7D. Canon may want to preserve this path.
I do think that Canon will position the 7D2 to be the king of crop bodies. This means more MP, maybe more FPS, and better video -- better than the consumer bodies. I suspect this is why the 5D3 and the 6D lack the STM video focus benefits of the T4i. Canon may be saving a better video focus system for the 7D2. However, I doubt that the 7D2 will get the articulating screen simply because it lessens the durability factor.
I hope I'm wrong. I don't really care about the video improvements. All I want is better low light performance -- and a locking mode dial.