No doubt about any of what you said above. Look towards WoC, RoL, and Disney Dreams where Disney has reduced or even eliminated fireworks from their nighttime spectaculars. They then installed permanent infrastructure for shows. Something tells me there's less liability in lasers, LEDs, and Fountains...Remember...the barges are there by choice...not lack of time/desire/funds to build permanent banks in the lagoon.
Fireworks sound cute..like something in aisle 4 at toys r us...
But they are basically a coctail of gunpowder, dynamite, nice caustic chemicals, and industrial pigments...
They spend all day repacking those tubes on the barges and at the artillery range behind the "safety" building and near the roundhouse north of Magic kingdom...
They don't want that stuff being done in the middle of a park...no way if it can be avoided.
Say something were to happen...and some pyro tech's hand gets blown off and goes flying 300 feet into the showcase at 4:30?
Can you imagine the consequences? If it landed in Canada...it could stop the stampede on Le cellier temporarily...and hold people back from the most mediocre quality/highest prices USDA subprime steaks on earth...
Too
Much of a risk.
Of course, WSL is one of the most horrible underwater environments in a Disney Park (about as far away from DCA's paved cement lagoon as you can get). Though that isn't stopping them with RoL so you never know.
The other problem with implementing some of the WoC technologies would also include viewing angles with projections. Maybe they could introduce viewing zones? I don't think they want to do that.
It will be interesting seeing what they do...