I just had a downgrade with the family on a 777 plane, but we were handsomely rewarded (which I appreciate) so no argument from our family, it's only a 3-hour flight. It was 9-across still, and I feel very cramped with the seats. I'm just 6'1" 160 pounds fine-tuned guy, and I feel the seats are already too cramp. My wife ,who's 5'5" and 120 pounds, agrees.
I keep walking up and down the aisles to visually imagine how is it possible for them to fit one more seat into the cabin? In the future I will fight tooth-and-nails to NEVER get downgraded to 10-across. It's insane to imagine how can people rest comfortably in that arrangement, especially on cross-timezone long flights.