Here's the seat maps:
Looks like they did a good job with this in the back. Lots of MCE seats, and preferred seats in 9-across. IMO, Better than the 773 with its too-small MCE section. There's even a few non-preferred (=free) seats in the 9-across section.
13 DEH as well as 18DEH were blocked on all flights I was looking at, as well as the very last row and 1A.
Everybody with 772 flights late in the year and row 31 assignments should review their seat assignments, though. Not that much fun stepping onto the plane with the new layout and finding oneself in the no-legroom-10-across section instead of the exit row on the current layout :eek
I guess I'd need to wait-and-see if 13 or 23 will turn out the new 31.