Stop comparing apples and oranges, the choice will never be between the 787 and 380 because the service will have be dence enough to sustain the 380, and take advantage of the cheapest seatmile available. Fx Iberia in the latest edition og Flight, they say that they have no route dence enough to for the 380. And that is a big company.
Glasgow will not have the problem of handling the 380 in forseeable future, because it only fits routs serviced by, or to dence for the 744 today. Maby around 100 airports in the world.
The composite fuselage of the 787 may not be so much of a brakethrough. When Airbus was designing the 380 they initialy wanted to make ALL the fuslage of GLARE (composite/aluminium material) but the launch cusomers stopped that, and made them have aluminium in the lower part of the fuselage (inpact area) because Airbus could not guarantee them short repair time with normal mechanics after minor impact with groundhandling equipment. Three weeks ago Emirates was asking Boeing for proof or demonstration that the composite fuselage would be repairable in short time and without a special team from Boeing