DUB is cleared to operate a FULLY LOADED B777 to UAE.
It won't be unrestricted I suspect but it will be a restriction that the airline can happily live within given acceptable loads and cargo revenues. In the burning heat of a Dublin summer (on occasion) with a full passenger and heavy cargo load, they might have to leave some cargo on the hottest days. The aircraft will never be "fully loaded" as it's never going to need max fuel and MTOW only going to Dubai or Abu Dhabi. "Fully loaded" would be the DXB-IAH run on the B777-200LR.
By way of comparison, CityJet frequently have to make decisions on passenger offloads at London City when the wind's not favourable and the loads are high. This does not stop them operating out of LCY however. Actually come to think of it, so do BA CityFlyer and they operate the most modern ERJ-190s. Hence, given that the runway length at DUB is comparable to GLA and BHX where Emirates have happily operating the B777-330ER for many years, it's therefore not a barrier at Dublin unless they really do have long Indian summers !
Dublin boasting the shortest main runway at the major airport of any western European capital city.
Were Aer Lingus suffering in summer flying DUB-LAX and SFO off the main runway on newish A330-200s? I mean were the payload restrictions prohibitive to profitability or was the route dropped for other more reasons?