I have a few thoughts.
Despite my handle here, I'm a Californian by birth and have spent probably more hours at Disneyland than Magic Kingdom (and I've only ever been on two trips to Orlando total.) I think this renovation could be very good in Disneyland. DL is a park that occasionally resorts to awkward visual barriers to keep lands from clashing TOO much, and while they don't do too much to separate the Mansion from Chickapin Hill they do use some obstructive trees when the exteriors could look closer to a match. Being able to extend New Orleans Square's design from the city to the bayou adjacent to the Columbia landing is a thing that makes me happy to think about.
Splash felt like a square peg in a round hole at MK, and it's going to require even more atmospheric work as part of the old south. I would actually hold off on changing MK's ride until the money is found for more extensive work. It's not like the whole mountain needs to come down, but the area looks a little too rustic.
I have never seen Song of the South or Princess and the Frog, but as my west-coast upbringing leaves me with no feels for Horizons or Journey Into Imagination except envy, this one hurts like few closures do. Most people's reactions seem to be cut along whether one is more interested in booking a visit around the old theme's closure, or the new theme's open. I'll admit I'm of the former, but mostly due to my increasing cynicism around the company's leadership. It's nice to see Tony Baxter get one last rodeo to fix his most problematic legacy ride, even if he's not super-involved, but Disneyland lost a fantastic Tomorrowland on an underfunded mandate to change that had Tony's name affixed to it. He's an excellent Imagineer but even he was not a miracle worker, and Splash is a concrete behemoth that will give that masoleum vibe if all the physical props and AAs are replaced with projections and screens.