Water, wind, mechanisms like hydraulic arms and rotating lights, pollution/dust/particles in the air and you have a maintenance nightmare. Biggest thing is that the visual downgrade of the area didn't result in a stunning nighttime show. And no matter how much water they pump trough the system, these barges will continue to be an eyesore for decades.
I'm sure Disney hoped the new show would save costs on fireworks but with all these workers on site it will probably not save any money.