I have both the 7D2 and the 6D2... The 7D2 is a really great camera especially in the line of autofocus. I was told at the Canon Service Center in Costa Mesa, CA, that the hot rumor circulating around the Canon folks there is that we can expect to see a 7D3 out next month.
Now concerning the 6D2... This had the capabilities of becoming a great camera but has fallen far short of that mark. Canon competes with Canon in that they are fearful of putting too many features into the 6D2 because they don't want that cheaper camera to cut into the sales of the flagship 5D Mark IV. As a result of these omissions, I would have a hard time recommending this camera to anyone despite the fact that you can often get it at a deeply discounted price. It has been discounted because Canon is having a hard time selling it. In fact Sony is kicking Canon's rear end with their new Sony A7iii - which is also an "Entry Level" full frame camera.
Some on my problems with the 6D Mark.ii are:
1. Canon plopped the AF system from the crop frame 80D right into the 6D2 with no alteration. As a result, the autofocus array is bunched up in the middle of the frame. You cannot use the eye level viewfinder and auto focus for head and shoulders portraits without being forced to focus and recompose since you cannot compose a head and shoulders portrait with an AF point on the subjects eyes. Often focus ad recompose is chancy if you are using a portrait lens like the great Canon 85mm f/1.2 wide open. Sure you can use live view. The dual pixel AF system in live view is great and covers most of the frame. However, I am forced to use some sort of viewfinder when I am viewing my image on the LCD in the sun. I use a Swivi viewfinder which allows me to better see the image on the LCD (https://www.adorama.com …_v_FUfxoAfkMaAiHDEALw_wcB). I find the Swivi better than the Hoodman Loupe for this job. Using single point AF in Live View is extremely accurate but, a bit slow. Using Face Detect speeds up the process considerably. But, I would really rather have an eye level viewfinder, especially one like the Sony A7ii with Eye AF.
2. The maximum sync speed is 1/160 second. I would rather have a camera with a 1/250 or even a 1/200 second sync speed, since I would be able to use regular sync instead of HSS more frequently.
3. The maximum shutter speed of 1/4000 of a second puts me at a disadvantage over a shutter speed of 1/8000 second when I want to shoot using a wide open aperture on a fast lens outdoors, especially in bright sun.
I won't even go into the other lacks: no 4K (which doesn't bother me but, which Canon should have added to the camera); no dual card slots I have not ever had a card fail but, I have had a card slot on my 7D2 fail (the second card slot saved my bacon); No USB-3 slot, just a USB-2 which doesn't allow me to use many of the Tether Tools cables.
I am sure that there are other features lacking but, these are simply the major ones that come to mind. I won't even go into the dynamic range problems with this camera.
Yes, the dual pixel AF in live view is great as is the fully articulating LCD with touch control but, IMO, these don't make up for the 6D2 lacking so many other features.