p.4 #1 · Moving to FF: Stick with Canon or Switch to Nikon?
This is a very good point and one I was thinking about today. I was looking through my Nikon Raws and comparing them to my Canon Raw images (similar lighting, scene, etc.) and, for all practical purposes, it is rare where the Nikon can push where the Canon cannot go. Does that make the DR difference irrelevant? Not at all - but it's not as monstrous a difference as some would have you think. Personally, the pixel count is really the key differentiator and the primary reason why one should pick a d800 over the 5d3. Obviously, if DR is the absolute end all factor, then the decision is easy.
I like tons of pixels - it's fun to play with as an amateur. But there are real burdens placed on storage and processing and the noise performance of the 5d3 is simply better (though the d800 is no slouch). The body advantages of the Canon go without saying. I constantly go back and forth whether I would prefer the higher pixel count or the superior noise performance. Both cameras have certain key advantages and which camera is better will depend on what you happen to be shooting at that moment.
p.4 #2 · Moving to FF: Stick with Canon or Switch to Nikon?
the grass is always greener, go read the nikon forums, they complain about similar things and start the "I'm switching to canon" thread on a weekly basis as well. Since you're not heavily invested in ff glass, and if you must make a decision right now it should be simple. For your purpose if DR is the end all be all, then Nikon all the way. If AF performance and high iso performance are the end all be all, then it's canon. That being said there is great work being done with both systems (and a lot of camera phones too for that matter), but I rarely see the photographer sign his/her work with camera make and model.