It seems that the "formula" for a 7DII is pretty widely agreed-upon; it would be surprising if it were not after all this time speculating, combined with the well-understood purpose of the original.
I think we can count on frame rate and RAW buffer to not disappoint.
I'd be surprised if the pop-up flash got deleted, particularly as it could be used as a radio/IR trigger.
Losing the mode dial would not be a surprise. I would like to see the rear controls align with those on the 5DIII - either layout works fine in isolation but I find it jarring to switch between them (IMO).
So here's my personal take FWIW:
- frame rate / RAW buffer will be fast/huge (how's that for playing it safe!)
- ultra-shot VF blackout time / uprated shutter (not necessary but would be nice)
- pop-up flash, will have RF/IR commander function
- 5DIII AF (this one has to be just about a given - I find it hard to believe there will be an all-new system)
- dual-pixel AF
- dual card slots (CF + CF please!!!
- textured rubber grip on the card door like 5DIII (I know, this is minor, but it sure feels nice in the hand
- LP-E6 battery
- true "quiet mode" like 5DIII (unlikley I know but it'd be sweet...)
- wi-fi / GPS (don't care but I assume it will be there)
- latest-and-greatest CPU for main functions, separate CPU for AF
- fixed rear screen. Whether it will be a touch screen is a good question
I think it's safe to assume the high-ISO performance will be slightly better than the 70D. Where will it be WRT dynamic range? I dunno but it better be real good - this is one area that Canon has been hammered with (justifiably or not) for quite a while now. But what I really, really
want to see is an end to fixed pattern noise / striping / whatever you want to call it:
I run into this from time to time and it bugs the heck out of me.