I understand why folks would be upset to lose a theme park attraction they love. Losing a ride isn't the same as a movie or song getting pulled. In the latter scenario, you can always keep a copy. In the former, it is gone forever and you'll never experience it again.
I won't knock people for trying to do what they can to save an attraction they love but most of the time, these changes are inevitable. So we just have to assess the situation and choose where to fight our battles and expend our energy.
At this point, I don't think there is much that can be done to convince Disney to reverse course. So we're left with the inevitable fact: SoTS/Splash is getting replaced with PatF. Should we waste our time kicking and screaming to Disney or on a message board when we know it's not gonna change anything at this point? I don't think so. Instead, we should move onto the next phase of the "grieving" process for theme park attractions: assessment.
Assess how this is going to affect your park-going experience. Share how you honestly feel, yes but if it's going to be a "deal-breaker" or otherwise overwhemlingly affect your experience in a negative way that you just can't see past: it may be time to move on to other things in life you find enjoyable and invest your energy there. Leave the park behind if this change really damages your experience all that much. It makes sense, right? If you're willingly giving your money to an experience that you know in advance you're no longer capable of enjoying, whose fault is it at that point that you had a bad time? I don't think it's Disney's.
If this change isn't a big enough "deal-breaker" for you to part ways with the park entirely, then just focus on the things there you enjoy and let others enjoy this one. Don't waste your time staying angry over things you can't change if you've already done everything you can. I do this with Mission: Breakout. I enjoy what little there is left for me in that park via Park Hopper ticket because the $50-ish price increase is still worth it to me. When there isn't enough left there for me to enjoy, I will simply stop going altogether and focus on Disneyland. -and if the same happens there, I will move on to find other things in life I love instead of wasting my time, energy and anger on things that are gone and that I can't change.
Sure, I'm sad to see Splash (in this incarnation) go. But I'd still visit Disneyland even if they demolished Splash entirely. I can take it or leave it. -and I'm in no way upset over this change yet because in my mind, it just makes too much sense. I mean c'mon, Splash is literally on the border of New Orleans Square and a land called Critter Country. PatF is a film that takes place in New Orleans centered around folks who find themselves turned into literal Critters. Touche', Disney. I ain't even mad, it's a smart selection and replaces a dated, taboo IP with a more recent one.
But is the overlay totally off the hook yet? Actually, no. Because all I care about is them doing a good job with it. If the PatF overlay is stellar, then awesome! But if they half *** it, I won't be mad because they got rid of SotS or used PatF, I'll be upset because they half ***ed it. But then I'd move on to what I do enjoy and leave the mountain behind.
I do hope it's possible for them to keep the name, Splash Mountain, though. At it's core, SotS or PatF, that's sort of what the attraction is. -and I think the name is both vague enough to distance itself from SotS while also iconic enough with the Disney fandom to be kept.