Interesting thought - wing flex as a shock absorber? I don't know. The heavier aircraft usually `ride' better in gusty conditions - more mass, therefore less acceleration for the force applied. It would be interesting to compare the 787 to another aircraft landing in the same conditions at around the same weight and at the same percentage of the max landing weight.
Great video! That wing flex is amazing - touching/dragging a wing tip in gusty crosswind conditions will not be much of a consideration with this airplane.(!)
I wonder how much stability is added with that kind of dihedral being added by the wings flexing?