Are all the mechanisms or whatever you'd call them all submerged under the water for Aquanura at Efteling? If not, I can't see something like that at Towers as it'd completely ruin the view of the lake. If they can get all the fountains submerged under the water, then I actually think it could be something that's worth Towers looking into getting, as the actual fountain show at Efteling looks spectacular, and could possibly work extremely well at Towers!
Zach, you also make some very good points about a parade. I've often found that entertainment at Towers in general, is something in which the general public just seem so uninterested in, so even though so many of us enthusiasts want to see more entertainment, it's actually not always worth Towers making the effort because the public just are not interested in watching it. Wasteland Bash is a good example of this. Put it simply – nobody really cared.
Characters are an interesting one. I can see for example a character such as Henry being pretty popular if they brought him back, updated the costume, and like you say Zach, is given a proper amount of guest interaction time for people to get to know him as a character and as the mascot of the park. Also, adding new, or making existing characters more prominent is also a really good way of bringing more characters back into the park.
Your last point I really agree with. The parade would have to get guests attention as something worth spending time out of their day to watch. It must have that wow factor so it can capture peoples imagination! I do think it's really a case of doing it in the right way as opposed to just writing it off as something they can't do. If they do it properly, I can definitely see a parade working well at Towers!