When the 5dMk2 gets phased out there will be a giant gap between the price of it and the 60d or its successor. Into this hole would logically go an entry-level FF body with still plenty of room for another. The 7dii would fill this space.
I see room for a 7Dii provided it'll have
dual card slot (sdx / CF)
dual Digic 5
APS-C @ 21-22MP
Better hi-ISO performance (hi ISO standard @ 25600)
Same current 7D price
While I could totally do without a slot for sd/sdx cards (I find them too small to handle, too easy to drop or lose in many outdoor situations), I could see it would make sense to take a wireless card.
The dual Digic 5 seems a given.
And, I would rather have better high ISO performance than more pixels.
8 fps is nice, but 7 or even 6 would be quite acceptable if the lower speed was exchanged for faster, more accurate autofocusing.
Given the nature of what I do, I'd like to see even better waterproofing so it matches the level of the 1D series.
USB3 would be great, but not a dealbreaker.
As for GPS, not really necessary. Seldom have I ever had to recall EXACTLY where I was when I took a photo.
Also, two things that I would ask for would be a larger viewfinder (the tiny image where it's hard to make out details, especially in the corners, is a major reason why I'm not a big fan of the current line of APS-C models) as well as a control dial (the one on top) that locks out, so I don't find myself in some mode not intended.
And, yes if I could have this for about the same price as the current model, I'd likely order one (or more) of the first ones.