Doesn't matter what the weight or flap setting was. Whatever it was it was incorrect for that takeoff. We use balanced field limits for takeoff, a balance between runway available, takeoff thrust settings, flap settings given the weight for that takeoff. Something there was wrong.
Improved climb, where you trade runway for increased rotation speed would cause a long takeoff roll. But given the lack of apparent obstacles off that departure I can't see the need for that type of takeoff. Again, something was not set correctly on this departure, or the crew blew some V calls. The lack of hard, gray surface in front of you is usually a good indication that you need to be flying.
And my resume is 28k hours, typed in 737/757/767 and Airbus 320 family.