So for the rest of you who actually own a 7D now, what would actually make you buy a newer model, if the sensor is the same? (take into account you'd lose about 15% purchase-price selling old-body and buying new one). And if the sensor is a new one (more than likely), what would you prefer from my options above?
Assuming I could sell my 7D and buy a 7D2 for a net cost of only 15% (about C$225), I would upgrade just for the chance to take that new sweetness out of the box! For me, the compelling option from your list would be same 18MP with any improvement in image quality whether that's a little better ISO performance, DR, whatever.
That pretty much sums it up for me as well.
I don't have a problem with more megapixels, but it wouldn't make it so that I have to have a new model.
I like the infrared trigger, but hate that the onboard flash overheats and shuts down in the middle of shooting, making the trigger useless. I'd like that fixed.
I would like to see an improved autofocus system. People say the 7D is far more sophisticated than the 5D, but frankly it's not always intuitive or simple to use. Just because most focus issues are the result of "user error" doesn't mean they shouldn't try to engineer improvements that will reduce those errors.
Reduced noise, higher ISO and expanded dynamic range are the main criteria.
Actually, this all goes back to something I've said before: Will Canon go for an incremental upgrade and focus on attracting new buyers upgrading from Rebels or will they go for major improvements to entice existing 7D owners to buy the new model?
I really think (and hope) it will be the latter. I think they learned with the 50D that incremental upgrades are risky and I suspect they have figured out that one customer in the hand (existing 7D owners) is better than two customers in the bush (Rebel owners who might or might not upgrade). A major upgrade will attract both markets, but minor changes will have most 7D owners waiting for the Mark III.