Taking a hurried peak at a 7D2 RAW file, it seems like the gain vertical banding issue of the 7D may be entirely gone. Only took a very harried look though. It's hard to tell because the 7D2 has such a small black outer frame area in the RAW and I didn't have the program to check for the gain type in the mids and brights but it seems like it might be gone, none of the shots are close to lens cap shots, but there is a chance they got rid of all or nearly all of the offset banding at low ISO all together. So that is the very good and impressive news with possible both the 7D's weird vertical gain banding and the typical Canon offset dark shadow banding very low or gone, maybe.
The bad is that the random read noise still shows no improvements since 2007 whatsoever, as far as I can tell. It seems like it will be extremely close to the exact same DR as the 7D. The read noise might even be a touch higher than on the 7D. Not quite sure yet, didn't locate quite the proper 7D file or my old numbers. Without the banding, the effective usable DR should be higher though even though it seems like the engineering measured DR might be anywhere from a bit worse than the 7D to a trace better.
Good news on the banding front. Looking forward to a dark frame to see what's really what.
Not really surprising for the rest, though. It's a revamped 70D sensor, with improved DPAF and apparently improved microlensing (which I actually think was also part of the DPAF patent, dual microlens layers). Other than that, it is an unchanged sensor. My guess is it's the DIGIC 6 chip ripping out the banding, leaving behind the random, if the banding has indeed been cleaned up.