I agree but the only Mirrorless camera the size of a D5/1D are the medium format cameras with a grip attached.Fair points, all. But I think all the brands are now trying to get on the mirrorless wagon and future direction seems to be towards small(er) bodies. Whether these are ergonomically suited to people with larger hands remains to be seen. I suppose one could design a body that is small and yet easy to use for everyone, but I suspect real estate becomes more precious the smaller the body gets and therefore harder to implement all the controls.
We all want the camera to have every possible option that suits us and yet be of the perfect size for our own physical attributes. Combine that with certain specific requirements that matter a lot to some of us (somebody wanted a three-way articulating screen as top priority) and you end up with a pretty darned good camera that will make many people ecstatic, but won't please everyone.
Small size too can only go so far. I for one would not be interested in the likes of the new Sigma FF - way too small even for me.
The one thing that seems to be obvious to me, the days of the full-sized 1DX/1DS type bodies are over.
Even the largest FF camera (LUMIX S) is smaller than the 5D/Dxxx cameras. I think a FF camera on par with the Fuji XH1 would be ideal in size personally. Not too big but not too small.