Alright, I have officially ridden the attraction and have a lot of thoughts. Not sure how novel any of this is because the page count of this thread jumped by 70+ pages since I ducked out to avoid spoilers so I apologize for retreading any ground.
Where to begin? Perhaps a goods vs bads to lay everything out and then some final thoughts. I would also like to state that I was coming into the ride with moderate expectations leaning positive and attempted to view the attraction on its own merits separate from its history as Splash Mountain (but then found that harder and harder to commit to).
The queue is nice and I quite enjoy the radio loop playing. The radio in particular gives a vibe that a tiny slice of New Orleans Square has come to WDW and does a good job at establishing Tiana as an important public figure. I absolutely love the lush greenery of the interior sets and dark lighting. The critter bands are very cute and add a great bit of liveliness to the spots they appear. The A1000s of Tiana and Louis are all a treat to see in full motion. Upon first hearing the rumors that there would be a shrinking/transformation portion to the ride I was highly skeptical it would be a good choice, but I think it turned out well and was a fun way to display the animatronic frogs much larger, as well as call back to the film. The primary thing to praise here is the finale scene and original song. The energy in that scene is great and really delivers the most complete part of the experience.
I generally don’t think the screens in this ride are too egregious or overbearing - they are actually quite minimal - but the shot of giant Tiana and Louis looking at the riders in the shrunken portion is the worst visual offender of the ride. It genuinely feels out of place and their dialogue could have been delivered with audio only to convey the same thing. As many have mentioned, there are quite a few empty stretches along the ride between characters. Not every ride has to be filled with animatronics to be good, and not every animated figure has to have complex motion to be effective at conveying what it needs to, but there is still a lot to be desired from the emptier scenes. The space between the 2nd band and the transformation dip drop is particularly empty, so much so that while on the ride you just instinctively look to watch the boat ahead of you complete the dialogue with Tiana right before the dip drop, only to immediately hear it again directed at your own boat. Though the A1000s are lovely, they are mainly used to just look at the ride vehicles and gesture at things. The finale is the only scene where it feels like the any A1000s are actually doing something within the narrative like dancing or playing music. Perhaps the greatest flaw of the ride though is that it lacks any poignant stakes, dramatic tension, or low beats. When designing a linear narrative experience a writer will typically create a graph laying out where the emotional high and low points of a story will be so they can fluctuate in a logical and satisfying manner. It feels to me that if you were to make something like that for this attraction it would be super flat and monotone with a lone spike at the finale. And while it’s true that not every attraction needs a well executed narrative or complex emotional arc to be really good, the issue lies in the nature of the attraction being a replacement.
I really tried to let this ride live on its own merits separate from Splash Mountain, but the positive elements of this ride come at the expense of another attraction, and they extract a heavy toll. Tiana’s Bayou Adventure is by no means a bad attraction and far from the worst retheme in WDW, but it does not live up to the narrative, emotional stakes, and technical feats of its predecessor. It’s very much like Runaway Railway in that sense; it’s quite enjoyable and a decent ride on its own, but it should not have been a replacement in a park desperate for additional ride-through capacity. Even with the social issues surrounding Splash Mountain and Song of the South, there could have been tactful methods of updating the plot and concept with different characters to deliver the same strengths of the experience.
TL;DR: Don’t give in to the hysterics of people saying this is the worst attraction WDI has ever produced because it is a decent ride; but it does not evoke the spectacle of its predecessor, making it hard to enjoy for those that know what came before.