Having gone through Sydney Aquarium (SEA LIFE Sydney) on monday, it makes me wonder how little time MW had to make those projections. They have a waist height white glump halfway into the wall in 1 area, but with projection mapping, they managed to put 3D coral and a moving clock onto it (I had to make a shadow just to check it was a projection). They also managed to project a walking penguin and the southern lights (Yes, at this time of year, in this part of the country, confined entirely within a water ride) into the waiting bay/unload station of the boat ride. Also, they have some really nice interactive mapping on the floor leading to a screen for the night time on the reef area, and the entire wrap around the final tank has floor mapping to look like water, then as you up the ramp to the final window, it shifts to sand. There's now a giant wave around the window and the floors mapping matches every part including another interactive beach part just infront of said window.
I'm aware that Merlin has a bigger budget, but when you look at the idea that this is going into 1 of only 3 venues, adding that its the venue with the highest upkeep of the 3, time is the only factor i can think of. While its certainly not lifelike, it really is close in that it's Merlin style animation, and was installed on a rather large scale like this.