Also I highly doubt we will ever see LEDs placed into the castle structure itself. The castle was built in the late 60s/early 70s and the designers placed flame retardant in it to prevent it from burning down as they should in a building that launches fireworks every night. The issue is the flame retardant of choice back then was asbestos. Drilling holes in (or disturbing any way) asbestos is quite problematic and requires extensive environmental protection, something Disney is never going to do for aesthetic purposes alone. The only way additional lights get put on that castle is with laying something on top of it (like light strands or roof panels.)