To jump the ship just for that seems unwise to me. There are many other factors.
There certainly are many factors.
But, for some of us, clean raw files that provide maximum malleability in post are worth the effort and cost to ADD the gear, not necessarily SWITCH to it.
My 5d2 was a PoS so I sold it and got a FF Nikon that kicks butt for clean files. Extra DR and MP are a bonus. 20 to 25MP were enough for what I needed in resolution, but I really needed NO pattern noise. Certainly miss the 5d2's superior live-view, D800's LV is terrible in low light.
I still use Canon crop bodies, along with a few Nikon and Pentax too. I use whatever tool I LIKE or is best for the shot.
I still like using Canons better than Nikons, but Pentax is very nice too if you don't mind lack of glass options.
If Canon makes a FF body as good as the Nikon for clean low ISO raw files, I'll likely buy it, especially if it arrives this year and doesn't cost more than $3-4k.