Wrong. I went full-frame, and I kept my APS-c camera for its advantages in high pixel density and fast frame rates over the full-frame.
Of course, the latter is not a general 'crop factor advantage'. You can get higher frame rates for lower cost, and as I've stated, lower cost is the main advantage of crop sensors.
Okay, I don't personally consider the 1-series as a viable option because of the body style, so I'm only comparing to the bodies I'd actually consider using (6D and 5DIII).
Not sure if this is what you mean... but I much prefer the "gripless" smaller bodies of non 1 series cameras. My 1DIV is a great camera, but the smaller 5D is a lot more comfortable for handheld shooing and easier for walk around.