I think that the old terminal will be demolished by the time the 787 enters service but looking at the A330/340 it will be a very tight squeeze at the moment to get past the old terminal onto runway 27. Again the 777 has a 199ft wing span so wingtip clearence will be an issue. Also stands 1, 2 and 3 could not cope with the weight which means that the only stands a 777 could use would be on the western apron. Also a 777 would be very weight restricted. The weekly thomsonfly 767 has a zfw of approx 79,500kg where as a 777-200 (which emirates use) has a zfw of approx 143,000kg which is almost double but only has approx 1/3 more power availible.