And I'm sorry that this basically excludes all non-mkiii owners, but ya'll haven't drank the Kool-aid yet.
Imho everybody who though about getting a 5d3 and then, considered the price, opted to skip it or go for a 6d/5d2 can have some valid opinion on this? So for me spending €3000+ on a 5d4 I'd like to have:
* red af servo indicator like they managed on the 1dx, but obviously weren't able to to on the 5d3
* spot metering linked to af point - yes, "1d feature", but should be very helpful for high contrast tracking
* rgb metering like Nikon & Canon 1d
* built-in rt controller (saving €300 st-e3 price & bulk)
* higher dynamic range at all iso, iso/res could stay as it is as far as I'm concerned