Well this was quite the news to wake up to!
Splash Mountain is one of my favorite attractions, so of course I'll miss it.
That said, I can still also acknowledge that while the ride did a fairly good job of distancing itself from SotS, there's still the elephant in the room of Zip a Dee Do Dah which took the chorus from Zip Coon, a song with a very unsavory history. Considering it's the big bombastic finale, I can totally understand that's a problem.
So at the same time, I'm not opposed to Princess and the Frog taking over. I still feel that's a very underrated film, and that is gonna' fit pretty easily right next to New Orleans Square in DL. An yes, I would've preferred a PatF ride built from the ground up, but I also feel the bones of Splash Mountain are way better suited for overlays than say...Maelstrom. There's a lot they can work with and they won't run into a capacity problem. Not only that, I do like that they're going with a sequel story instead of trying to retell the movie. There's a lot more freedom on what they can do, and make it fit nicely.
Finally, knowing who's on board the project, I have a lot more faith in this. Tony Baxter coming back to work on this is huge, so if it's got his blessing, I look forward to see it.
Not to mention, I remember when Guardians of the Galaxy: Mission Breakout! was announced and many had a meltdown. But then it opened, and it surprised the heck out of people on how good it was, myself included...to the point where that ride is one of my favorites! Ultimately, when it comes to any overlay (or any ride in general), it all comes down to the execution. Which none of us know until we ride it.