[Brightcolours]

The total package is very different. Number of focus points

The 6D has the more powerful AF system with its low light capable (and otherwise also very fast and good) AF system.

, number of MP's

24 vs 20mp is not a big difference. And 20mp is already enough for very big prints.

, size and weight of camera

Yes. And better handling of the bigger camera.

,live view

And missing OVF. 

and focus peaking.

Oddly enough, I do not need focus peaking. If I did I would install a different firmware on the 6D with focus peaking (magic lantern, at no extra cost)...

 

My point was that you were comparing 24-70mm f2.8 DSLR packages with a 24-70mm f4 A7 package. Better to compare with a 24-70mm f4, which makes the difference quite a bit less.

 

Obviously, the A7 has some advantages. And quite a few disadvantages too.