However, Canon seems to be trying to go the other way - segmentation. The idea being, apparently, to get people to buy multiple bodies for different purposes instead of buying one do-it-all body like they did with the 5DII.
Segmentation is fine as long as there is a real differentiator. For example, the 5Ds is clearly a differentiated camera--sacrificing high ISO for low ISO/high MP. Let's see what Canon does to differentiate the 5Dc and 5DIV, if that is in fact what they are doing.
I suspect your concern is that they will stupidly cripple one of the bodies or lose out on the "jack of all trades" body. We'll see.
But, say they release only moderately differentiated bodies, say a 5DIV with weaker video functions (no 4K), but optimized for stills (24-28 MP, AF, fps, etc) vs a 5Dc (rumored specs - 4K, 18 MP, etc). Both could be valuable bodies. I'd personally opt for the 5DIV specs. But those that do more video would likely opt for the camera with the 5Dc specs.