But the extra reach is nothing, I never understood the hype of Crop Vs Full Frame Reach. I went from a 70D to a 6D and i will gladly say the reach difference is like half a inch on the image, I even put a 1.4x Extender on the 70D and the difference is again, hardly anything and for what it cost ($500), it's a waste of money.
I thought about getting the 7D Mark II for Wildlife but i might just keep the 6D as Image Quality will be better. But i do want to see RAW samples at High ISO, It's looking like the 70D ISO performance but it might be a stop better.
If you don't need to back up or zoom out to compose your scene with APS-c, FF "Image Quality" is completely irrelevant. You need the FULL FRAME for "full frame" image quality.
Now, it just so happens that a 1.6x crop from the 6D has noticeably less noise than a 7D at high ISOs, everything else being equal including displayed subject size. However, this is not a "FF" quality per se, but is model-specific. The 7D2's read noise is a stop lower than the 7D's, and is much finer, so I foresee my 6D staying home when I go out shooting birds when my 7D2 is delivered. I use the 6D now when the light is low for noise and AF purposes, but I expect those edges to disappear.
Until Canon releases a FF camera with a lot less read noise than the 6D/5D3/1Dx, the 7D2 is going to be the Canon DSLR for FLLP (focal-length-limited photography), in all lighting situations.