DXB-ICN gets my vote too. You get to lounge in DXB and access to better catering ex-DXB.
The 3:30am departure would be the sticky issue. The airport will be
very busy between 11pm and 2AM which means a lot of boarding calls and final calls heard from the main level and the lounge.
In terms of actual flight duration, don't sweat over it. ICN-DXB is only an hour longer (approx 9 hrs) than DXB-ICN.
http://flightaware.com/live/flight/UAE322
http://flightaware.com/live/flight/UAE323