ICN-JFK roundtrip in Y class. B777-200ER with 3-class configuration was on both flights. The seats are not slim they had thick seat back. Although seats were comfortable thick seat back ate up some space. FA's were asking passengers to return the seat back upright at mealtime. For those who choose to sleep were bothered by this especially at the second meal service as one passenger was complaining about waking him up. Both flights were full but the service was flawless except for the mealtime wake-ups. Inflight entertainment system improved a lot in terms of contents. Overall great experience but surprised by not adapting space efficient slim seats as other airlines or even its own 747 fleet. Asiana Airlines 747's are equipped with slim seats and 10.6" AVOD.