In my option this camera is a disappointment to be honest. And I currently use a 6D so I should know about it
And here the reasons why.
Despite the fact it lacks 4K (which to me isn't that important) but as the market seems to have everything 4k at the moment then yes leaving it out is a risky move. They could have had it 4k in a compressed format and made that format be average at best. (but it would still have been 4K and suitable for youtube) They should have released 5Dmk4 with 4k with all the format serious videographers needs.
USB connector that's 15+ years old, at least usb3 or usb type c (at usb 3 speeds)
one good feature, 45 focus points but these are focus points that are designed for a crop sensor so there's no point in having them in a FF camera. So it's a focus system from a camera released in Feb 2016. Which means that either the 90D will have the same AF as the 80D (so that means the 90D wouldn't be that much of upgrade)
Bluetooth, really? I don't get that.
Could upgrade wifi (upgraded chip to 802.11ac perhaps) but no biggie
Dual card slots, yes, the cheapest Nikon D610 has got dual card slots. or at least upgrade the card slot UHS speed 3 so so you get fast transfer speeds.
There are features on here that are out of date, this should have been the 6D that should have been released 18months ago. Since perception is reality then it seems that this camera has caught up to what everyone else has done last year. So when the likes of Nikon release their replacements, this camera is going to look even older.
The main reason why I wouldn't upgrade this camera from the 5 year old 6D that I am currently using is that this camera is already looks old. If I can going to spend my hard earned cash then I want it to look updated. it doesn't have to be revolutionary but it does have to look modern. Modern in an age where the change of tech happens quickly