I fly DXB-AMM and vv every year and have never had a problem (albeit usually in F, sometimes in J). The afternoon/evening AMM-DXB is always full and boarding is late and chaotic. But that's AMM for you (probably the new terminal will fix this--I hope).
The morning AMM-DXB (902) is a pleasure. The airport is less busy, and the fight has never been full (I know it comes up full as 901).
I am doing BEY-DXB tomorrow for the first time so it should be interesting to compare (but only in J).