Please,.. "superfast hybrid autofokus"? No, nono, no, it's fast'ish. Under optimum conditions (strong light) and stationary object, it does 80 milliseconds, which spelled out is the same as one tenth of a second. That is not as much the problem as the wavering performance in demanding light, particularly with tele lenses, poor accuracy and poor prediction. Hybrid focus is an improvement, but there's no substitute for the large, multicrossed PD elements used by SLR and SLT cameras.
"Probably the biggest stumbling block for a DSLR fan is the lack of an optical viewfinder " Umm, no. I sure like the lagless, direct contact and the real estimate of lighting differentials that an optical viewfinder offers, but the biggest stumblingblock of mirrorless cameras is their poor readiness, poor readiness comfort, poor battery performance, and poor battery comfort.
I have the highest regard and respect for Samsung's camera division. They do hi-Q stuff, they are serious. But the mirrorless systems with bigger sensors live in a sort of no-mans-land. There's no sensible use for them. They fail to be more compact, because the lenses remain the main bulk, and their weight and size is governed by the size of the sensor. They also fail to be more compact because, actually, they're not really. The truth is, they compromize their performance and capacity to shrink into a small house. And you can do that with an SLR too. Look at Canon 100D for instance.
Mirrorless excels as compact cameras with a limited lens, wide or normal, that are small enough that you can take them along always. Nex 5T and NX300 are good examples, but even better is going down in sensor size to m4/3, for an even smaller camera. Like Panasonic GM1 or Olympus PM2. A world apart in image quality from pocket cameras and mobile phone cameras.
But as system cameras, mirrorless is a redundant, castrated and expensive failure.
Cheap DSLRs from Nikon, Canon and Pentax offers so much more for less money.