I'd be Ok with this. The ride itself is a simple log flume - the scenes are cute but not impressive technically, and the movie it is tied to is problematic for Disney.
Imagine a more imersive trip...same water track but upgraded scenes, maybe some cool innovations (like the mist cloud at the beginning of PoTC) and the PATF storyline.
I don't think it is reasonable to expect "forever" continuity in such things, especially with this kind of ride. You can expect Mickey and friends, new and old, to always be around - but otherwise I'd hope WDW will be always slowly evolving.
Who knows if the rumor is true but I'd be Ok with it. I can ride the old one on youtube anytime.