If I understand this correctly, the problem was failure of the nosewheel to retract.
Apart from the obvious problems of increased drag causing a slowdown, and the extra fuel burn, is there any reason why it could not have flown to HKG, where there must be perfectly good maintenance facilities, for the problem to be dealt with there, given that at some point it had to land anyway? It would have caused less disruption to passengers, even if slightly delayed, and less wastage of fuel and environmental harm.
Would the extra fuel burn have meant it couldn't make its destination?