To be clear, I make no final claims yet to either TBAs being better or worse than the Splash they replaced because I haven't been on either one yet. And I have only been on the Florida one a few times, many years ago. My statements regarding its superiority are just echoes of sentiments seemingly shared by the majority of folks I've encountered in the parks and within the online realm. Despite only being on it a handful of times, though, I would be inclined to agree with them.
Although the debate about which Splash is best honestly feels like a moot point when Tokyo's exists. The fact that OLC cares enough to actually maintain their attractions automatically makes that one the best one, in my book.
I think Splash Mountain had a better storyline (from what I have seen so far) but I will still reserve judgement for which attraction I think is "better" until I ride it for myself. While not Splash's fault, the fact that stateside-Disney allowed Disneyland's to fall into such a state of disrepair will not do it any favors in my eyes when comparison time comes. And although storyline helps, it's not an automatic indicator of superiority. Attractions like Mansion and Pirates are a bit vague/simple in this regard while attractions like Space have basically no storyline whatsoever. Yet, these are beloved and classic attractions still.
Will Splash be the superior attraction to Tiana's in Disneyland? If Tiana's has the same issues as WDW's then in theory, yes. But a better paced Tiana's whose effects work/are maintained over time may give it the edge for me over the broken lighting and figures or exposed work ladders in the Laughing Place that I've seen for many, many years in DL.
But the jury is out even on that one because Tiana's figures and effects have been suffering
heavily over in WDW so far. Not to mention the huge amount of downtimes. In a perfect world, our parks would give their attractions the love that OLC does. But that'll obviously never happen.
TLDR; I'm hopeful that a "working as intended" Tiana's out in DL will be better than Splash in the state Disney had allowed it to degrade to when it closed down. Judging both with broken effects? Splash would likely have the edge because of the stronger storyline. But Tokyo's Splash beats all other variations of Splash or TBA, at the end of the day.
In other words, I should probably just book a trip to Japan.