Josh D'Amaro speaks on the matter:
"We actually have been working on it for well over a year. In fact, I was a part of those conversations over a year ago. Listen, our stories evolve all the time. I mean, back from when Walt started Disneyland back in 1955, he stated that if we would continue to evolve our stories, that they're never ending, that they'll always be contemporary. And I think that that's what you're seeing with Splash Mountain.
I keep using the same word, but I'm really proud of this team and what we're doing on this front. I think Splash Mountain, no doubt, is a sacred attraction to many of our guests. And I think you're going to love what we're doing in making the attraction even more contemporary."
Make if it what you will. It is somewhat telling that -- every time they need to justify making a change -- they drag out some variation of something Walt Disney said once (in contexts that aren't really reflective of what he likely meant).
The "you're going to love what's coming" is the standard operating procedure when talking about replacing a beloved attraction (I still remember Universal's statement announcing Jaws was going away, and it was very similar). But if "making it more contemporary" means significantly fewer animatronics, it's going to be difficult for me to "love" it.