I suppose you could say that the size difference isn't significant.
http://camerasize.com/compact/#567,624,ha,t
But I would say it's significant
I suppose you could get into the argument that there's no difference once you fit a 70-200mm f2.8 but the A7 body is always going to be smaller and you have the option of using a compact lens and ending up with a combination that the Nikon just can't slim down too even with a lens cap type lens.
) which still works as well as it did before the Mk2 was announced.
Actually it's Sony who are loosing cash in their camera division (rather than sensor division) though recently they made a small profit. Nikons losses have been writing off expenditure in non-Camera division and profits in the camera division are healthy (even if their market share is falling).
Nikon is in a bit of a pickle ATM but I think the longer term question is their apparent reliance on Sony for sensors, while Canon make their own.
I suppose you could say that the size difference isn't significant.
http://camerasize.com/compact/#567,624,ha,t
But I would say it's significant
I suppose you could get into the argument that there's no difference once you fit a 70-200mm f2.8 but the A7 body is always going to be smaller and you have the option of using a compact lens and ending up with a combination that the Nikon just can't slim down too even with a lens cap type lens.
Actually the a9 vs d5 size comparison is more than 2cm.... 2m more like lol
Sell a camera with small size as a 'benefit', and then sell an extension basically admitting that the camera is too small for some people. Genius. 
Same as the grip they sell for the RX100 cameras which makes the cameras easier to hold. Design it right in the first place, and these are not needed. But then you wouldn't be able to charge people for them Ah!, I get it mow. 
There is a slight size difference between the a9 and the D5.
In the video I posted above though, one of the chaps says he feels the a9 is too small, and benefits from an added body extension Sony sell. That they will sell you for £130 btw, with no other benefit other than making the camera larger.
Seriously, if they had mad the a9 slightly larger, they may have been able to fit XQD slots, and also made the camera more comfortable to hold.
There is a slight size difference between the a9 and the D5.
In the video I posted above though, one of the chaps says he feels the a9 is too small, and benefits from an added body extension Sony sell. That they will sell you for £130 btw, with no other benefit other than making the camera larger.
Seriously, if they had mad the a9 slightly larger, they may have been able to fit XQD slots, and also made the camera more comfortable to hold.
Lets see if/how Nikon and Canon respond to the Sony A9, they still have certain advantages along with the more complete lens line-up.
The chap in the video I linked to above said that his knuckles rubbed on the larger lens, but with the grip extension he could angle his fingers so that didn't happen. I suppose it will affect different people in different ways depending on the size of their hands and the lenses used though.
I'm all for 3rd party alternatives, especially when manufactuers charge extortionate prices for accessories, but even £40 for a bit of metal seems a bit harsh imho. For some cameras you can get a grip that adds more power, remote control etc.
Those that are considering buying or have bought a camera are also quick to defend any perceived slights against their choices. As a relative outsider, it is sometimes easier to query design choices. No camera is perfect after all. And it is something to talk about anyway. with all my cameras.
