It does still leave the SLR with a very sizable advantage in certain areas:
- Zero lag TTL viewing (even a Genlocked EVF like the Samsung NX is still 1/60 of a second delayed)
Actually, I think it's less than 1/60th of a second -- which is already invisible to the naked eye. So it's an invisible lag, which will only get shorter and shorter as the technology speeds up.
- Less heat coming off the sensor and electronics allows the user to use the unit continuously for longer
I've never seen extensive reports of overheating issues, except in video use (from mirrorless AND dSLR). In fact, along a similar note, a mirrorless camera can last longer, without the wear and tear of a flipping mirror.
- Battery life is substantially longer, as very few electronics are powered most of the time. Most DSLRs clock in at 4-5 times as many photos as a mirrorless of the same size battery
Just a matter of needing more efficient batteries. The battery life of the NX1, for example, is longer than many dSLRs. For example, the NX1 has a battery life of 500 shots -- that's longer than most Canon APS-C cameras! So we can already cross this off the list as a major concern. Not like mirrorless camera batteries die after 20 shots while dSLRs can last 2000 shots. Overall, on average, dSLR battery life is longer than mirrorless But as shown in my example, there are already mirrorless cameras with longer battery life than many dSLRs.
- Much faster autofocus with all lenses,
Gotta sound the buzzer on that one. It was true a couple years ago, no longer true. A camera like the A6000 already has faster AF than most dSLRs. Can still wait for more reviews, but early reviews suggest that the A7rii can autofocus Canon lenses just as fast as a native Canon camera.
And then there are also practical differences caused by the camera market:
- DSLRs have much larger lens sets offering a huge variety of glass to resolve any particular need. Off of the top of my head, Nikon has a half dozen exotic telephotos, four teleconverters, five Macro, three perspective control, four f/2.8 zooms, five f/4 zooms, and a full stable of non-exotic primes from 14 mm through 300 mm, including ones that allow discrete bokeh control ... and that's just in current production.
Again, mirrorless are moving towards universal mounts. So you can take all those exotic lenses, use them on mirrorless, without compromise.
- DSLR ergonomics are developed over decades of experience, and on mid to high end ones everything can be adjusted with the viewfinder to your eye and by feel, and the camera is designed to get out of the way and just shoot.
So just build a mirrorless with the exact same ergonomics.
Now, the practical summary of all of this:
Yesterday, a hawk flew over. I swung my camera up, mashed AF-ON and my shutter as soon as it was at all in my viewfinder, and my D7200 rattled off 43 perfectly in focus shots from a 300 mm f/4 with 1.4x teleconverter as it flew over. Even the Nikon 1 system, holder of the fast focus crown for mirrorless (smaller lenses, after all), can't compete with that, and I know it, as my fiance owns one (that I'm a bit jealous of, might I add, but that's another story). Every single one, it didn't even miss the first shot, at 7 FPS, when the lens was focused at 10 feet and the hawk was at 200 feet.
And we are getting to the point where you can do the exact same thing with mirrorless -- Even use the same lens, same teleconverter. But get a perfect 11 (A6000) or perfect 15 (NX1) images, instead of just 7.
You keep banging on about mirrorless like it's the second coming - it's not, and it has quite a ways to mature. But it's good enough for you and a lot of other people, and is rapidly going to have a larger market penetration and in 5 years (my guess) surpass DSLRs in sales. But they can never completely replace SLRs, simply because to do so, they must give up all of their inherent mirrorless advantages and incorporate a long throw PDAF sensor.