A "super G series" ,,, the image quality they want and the single lens they want ,,, The reason why mirrorless EVF technology will be replacing the SLR in essentially all camera categories is because that technology offers superior performance, size and price. A few action sports photographers will hang on to their mirror boxes until sensor based follow focus outperforms DSLR phase detect. To try to pigeon hole mirrorless into some little camera sub-category is not going to stop its advancement through the camera ranks.
Of course all cameras competing for flexibility and IQ should have interchangeable lenses.
If anything should be pigeon holed into a low IQ camera category it is the fixed lens.
Unfortunately, as it is now, EVF is still pretty slow in response to the change of scenery and being expensive. There is only one camea that is with the built in EVF (Fuji X100). The rest are add on EVF externally. That will make the camera bigger. Also the focusing speed of the "mirrorless" are slow, compare to the DSLR. In other word we may still need to live with the mirror for a few more years.
As for fixed mirror equals to low IQ. I am totally disagree on it. If you look back into the history of camera, there are many camera that are with fixed lens with IQ to be better than interchangeablelens camera of the same time. Just to name a few: Rollieflex, Rolliecord, Retina etc. The IQ depends how the lens is made (and hence pricing), not whether it is fixed or not.