that would be such tremendous fun   In terms of cathedrals and such you could get such a great sense of the layout which you often cant see from the ground or from a plan  In the case of Wells Cathedral for example when you look at a ground plan it is apparent that there is a long central axis which is crossed by three arms What the plan doesnt tell you is that the first transverse arm is actually two projecting towers the second transverse arm is the main transept which is the same height as the nave and has a lower aisle on both sides and the third transverse  arm is a pair of projecting chapels that are only as high as the aisles On the plan alone without knowledge of the conventions it would be very easy to miss the importance of the first arm towers and overestimate the size and visual significance of the eastern transept off the presbytery  You could also see details of the West Front statuary that are only visible with binoculars It would be a tremendous asset in checking out the state of the stonework without a cherrypicker  You can also see the relation of the building to its environs Wow   On the other hand hovering midway up a facade in order to counteract perspective is not the way that an architect ever intended a building to be viewed The ideal height to view a welldesigned building is human height  The main exception to this is in the interior of a theatre where the architect has generally designed the best view to be from the more elevated seats not the stalls not the Gods but the Dress Circle  Thanks for your message Rod