I have been thinking about it and, well, it's a bold move; maybe only they can make it and be happy, but do you remember when Leica got out a digital rangefinder camera without screen? No live view, no EVF, just the normal rangefinder patch...
Ok, it's maybe silly not to be able to watch your pictures and see if you need to correct some things, but it's bold, it's a brave movement, a statement of pure art and craft: if you know how you want the picture, you can just make the picture: no gimmicks, no nothing.
I agree with those who praise the EVF for previewing the shot, having the histogramm right there, and so on... But it makes you... comfortably numb (paraphrasing that great music group). It's not an aid for your walk, it's a vehicle to moving you around. It's the same when people tells you: don't shoot with a zoom for a while: get used to a prime and zooming with your feet, because you will discover new perspectives, new points of view, new pctures, in definitive, when you do it this way. Zooms as framing tools are a bad habit. Zooms should be tools to get the picture in the right mood: wide landscape, or maybe a zoomed in mountain range? Not just not to have to crop too much in post... If the rules are. wide for landscape, normal for street, groups, lands, maybe portraits, and the tshort tele for portraits and long tele for wild life; then that's your zoom lens usefulness. And if you want to breat the rule, and make a 24mm portrait, then you know what you are doing.
I purposely keep my screen off, I don't want to pimp my pictures, every time I shoot. I might check metering, this is an advantage, to be able to check in situ, but it's not a fundamental part of taking a picture... It's not a necessary part of the craft... Pros will want to have everything and the sink kitchen, because they want to be as effective as possible, to create the best job with the less hassle and less work as possible. That, of course, needs not an EVF, or a histogram or anything: 120 years of Photography demonstrate it is possible, in manual focus and in manual everything. Of course, the number of keepers might be higher nowadays, with the wonderful cameras we have, the amazing continous AFs and all the shiny things. They are useful tools, not needed tools.
So maybe a DSLR without a screen would be amazing: you have your card(s), your command dials, your display with all the parameters, and all the modern things, but you cannot chimp. Of course, someone might be able to tether to an external monitor: more power to you, pal! But you don't usually go around with a monitor on your armpit, do you?
Of course, bold Leica move. If Pentax does get a no chimping DSLR, there will be those who ask for an EVF! Ah, cheaters! LOL
Now I am eager for Photokina! :-)