If they had disconnected the A/P when the engines failed to respond to the manual throttle movement and flown the aircraft towards the grass, I bet they would have had enough energy for a decent flare.
I somewhat agree. Not only that, if they had put it onto manual, decreased demand on the engines then the blockage/inleakage/cavitation would have subsided then full thrust may have been regained.
However, I don't feel that we can suggest that the chaps on board did anything wrong. There were no fatalities, no serious injuries, and they landed in a distance shorter than I land a Piper Cherokee into.
T.