Alternatives: Canon 5Ds (5DsR), Sony A7R (or mark II if it comes out), and Nikon 810.
Well, I can say that a friend of mine who broke his 5d2 due to the non-existent weather sealing just purchased a used d800 on my advice. I begin to regret this because....
... now I'm getting daily enthusiastic mails from him, wishing his Canon would have been broken earlier to force him to switch. Admittedly he's a landscape and high-dynamic range guy, but for that application the 36mp 14+ ev Nikon sensor blows Canon out of the water. I don't think the studio "crop upscaled" 5ds is a competition here.
DR: Expose correctly, capture in RAW/CR2. It is extremely rare that this does not do the job. If not, it's HDR time
*Snigger* oh my it's Canon enthusiast time, but really, try that on moving cloud with light beams shining through them and people walking about the scenery. Or anything that moves in high contrast like leaves or grass, actually.
Don't misunderstand me please, I'm happy you're happy with Canon and totally love my Canon gear, but as far as landscape as dr is concerned you cannot just compensate with bracketing even if you accept the usability hassle.