The only real "crop factor advantage" is that the sensors are cheaper, and thus the cameras they are in are also cheaper.
... and the mirror is smaller, so with the same level of engineering of the 1dx a crop body could get a much higher fps than a ff - at least it's my guess that the mirror size and mass is the limiting factor. Of course this is very unlikely to happen even with the 7d2 since mirrorless gets a much, much higher fps at no cost.
Another "crop factor advantage" that comes to my mind is that you can put it into smaller (and shallower mirrored) bodies, I always found that a crop sensor in a 7d size body looks very strange and lost.
Sony currently is going for latter, here in Germany the environment is plastered with Sony adverts not only telling us they own 50%+ of the sensor market, but showing their new mirrorless aps-c right next to their traditional dlsr line, comparing the size in a way favoring the mirrorless design as it has the same iq in a smaller package.