Last time I flew Malaysian to LHR at the beginning of the year, the A380 was only about a third full in economy. (Crew indicated this wasn't unusual). Flipped up the arm rests and stretched out with 3 seats to myself. Seat pitch wasn't an issue but it didn't seem much different compared to Emirates. The only other things I remember about the flight was the economy breakfast was inedible and the service was so-so.