Some illustrative history: set the calendar back ten years. The Contax N Digital is released as the world's first full-frame digital slr. 6MP sensor, 3 FPS top shooting speed, so expensive and time-intensive to develop it basically sunk the brand.
Ten years--an eternity in digicam technology advancement; an eyeblink in backpacking technology advancement.
Since, a dozen or more FF dslr models have been rolled out, along with but one FF rangefinder, the Leica M9. I won't go into size, weight and pricing calculus, suffice to say they're all rather dear, heavy and other than the Leica, massive, and yet backpackers, including "lightweight" aficionados who hang here carry them because they offer unique photographic qualities.
The trap is to misinterpret what the RX1 represents. This camera could not have existed two years ago, much less ten. It breaks several molds and gives full-frame results--yes, unique and distinct from smaller formats regardless of whether that look is something your vision desires or requires--at a shocking fraction of the bulk and weight.
At three grand it's not a camera for me (I wish) and perhaps not a camera for you, but it represents a paradigm shift that will be followed. Like the micro-four thirds prototype unveiled a few years ago, it's an entre to an entirely new camera category that has those in the know thrilled with what's to come. Lightweight backpackers are dead-center in that cohort.
Not a zoom? Only a limitation if you allow it to be. For years my backpacking camera was a Contax T3--coincidentally a high-end compact with a fast, sharp 35mm lens the equal of any slr lens. Some of my best backpacking photos were taken with the tiny Contax, and the parallels with the vastly more competent Sony are many. I'd certainly prefer an EVF to an optical framing thingie in the hotshoe. That will come.