Soooo... like the ones in the Little Mermaid ride? That doesn't really fill me with confidence...
Whatever meets the requirement of figure(s) that can be maintained consistently and keep the show looking nice. Of course in a perfect world, I'd love to see super advanced, highly animated figures throughout the attraction but in an aging, soaked structure like Splash, I just don't see it happening. So I'm willing to compromise if need be.
Certainly I'd like things to be a step above Mermaid, but even that attraction has some nice ones, as others have pointed out. One must also take into consideration that Mermaid is an indoor, dry,
slow moving dark ride. That makes the static figures used throughout the attraction way more offensive to the eye. Splash is much different in terms of speed and action once you get down that first drop. If you pack the scenes with enough detail and movement, I think figures even at or a step above Mermaid's level could pull it off if that's what they need to do in order to keep things looking good.
Some key, heavily animated characters at major points would be nice but I'm not gonna expect every one of them to meet that level during the attraction, I think I'd be setting myself up for disappointment. Heck, even now, during the climax of Splash, as we ascend the final lift, we're met with little more than some audio, a projection box and an incredibly basic (nearly static) Brer Rabbit.
It can work, they just need to do it right. I'd love for them to shoot above and beyond and build something that works consistently but with the current track record of overly ambitious effects causing so many problems, they should probably take a step back when using Splash's aging infrastructure.