FWIW, I'm not sure I agree with the commentators that this is a "bad" landing. It's an A380 -- the biggest passenger jet ever -- in heavy crosswinds with only 5500 feet of runway in front of it. They had to put it down quickly and, if need be, firmly. Had they floated to a smooth touchdown, they might not have been able to stop before the end of the runway. (That's bad)
Still, the video of the wing flex is remarkable. How strong are these wings? Check out this video of the 777's ultimate wing load test. Badass stuff.