I am for one hoping that the Digic 6 will in combination increase the useable ISO and speed on the 70D. 100-51200 (expandable to 102400) would be nice. As usual, that would mean that about 2 stops from the limit would be actually good, and 12800 could be used in a pinch, and the excellent levels upped to 3200-6400.
I am ofc not holding my breath...

But, 100-25600 (51200), 6400 in a pinch, 3200 still excellent I would think would be enough to get this 70D off the shelves. (1 stop over 7D, and DXOmark around 1600)
...still not holding my breath...