If they can launch fireworks, they can send the drones up to that height. Its just a matter of aligning with the FAA. Drones are going to be a lot more flexible in that respect - and a lot more neighbor/kid/environment friendly. Don't discount those advantages. Besides... they are more versatile and cost effective. Oh... Jungle Book is a surprise hit? Program a Jungle Book sequence to replace the Wreck it Ralph sequence... Boom... done.
Don't need a body of water. Hollywood studios could use the fireworks launch site.
The key pieces to this are size, and volume. If they can get the body of the drone to 1/2 the current size, and 3-4X the volume in air at once... then yes, this very quickly becomes a pyro replacement. Watch the Intel video... particularly the launch sequence with flashing lights. If you look at the Intel site, and review the "100 drone" launch videos, you can see where they more closely simulate fireworks with good effects - and that is using 100 drones. They are already at 500... they will scale this quickly to over a thousand - 10x the drones used in that effect.
Imagine the Hollywood studio Star Wars... projection of the death star that rises above the buildings... drones used to create a death star outline... .. X-wing projection fires two "torpedoes" at the drone death star... and then all drones explode outward in an explosion... That is the effect and the concept. Characters, text, shapes... simulated actions.
Its exciting that it is coming so soon to Disney Springs so people can see it. I would not be shocked if Magic Kingdom's 50th is 30% projection, 50% drones, and 20% pyro. If you look at where its been in the past 2 years... project that out 3-5 years? Particularly when you have motivation of cost, flexibility, and customer involvement (no more crying kids from noise).