I don't need more than the 50c back produces. The problem I have is the cropped sensor.
I shoot outside - I don't shoot in the studio and I do very little portraiture. But I have been thinking about upgrading to a H6D-50c but much of its capabilities (wi-fi, True Focus, glitzy lcd screen etc.) are for me otiose - nice but not essential. I love the H system but it is also very heavy for those of us who shoot on location without assistants. For my work on a 50c I would probably be happy with the 28mm or 35mm, 50mm and, less so, with the 80mm lenses. I also have a 120mm Macro Planar for the V system which I can use with an adapter but I haven't got the 35mm and 50mm lenses (although I do have a 50mm CF).
So if I went with the H6D-50c I would probably end up buying both the 28 or 35mm and the 50mm lenses. If I then upgraded to the H6D-100c I would still probably buy the 50mm and use my existing 80mm.
But that is a lot of money - and a lot of weight. So my hope is for a much lighter body with the 50c sensor, at a lower cost than the H6D-50c and which for the same money would allow me to buy the wider lenses as well.
But then you seldom get what you want.