Contrary to popular belief, he never worked with Disney Imagineers. You can read about it when I interviewed him about it where he said point blank (and is referenced in my audio transcripts) that it never happened.
Tim Fisher was the CEO for all of those rides that were both themed and lightly themed so i'm not sure what your point actually is. If it's that parks have used IPs for rides (and that's bad) i've got news for you - everyone does it because it works to drive gate. I have no doubt Fisher picked this up at Paramount Parks and instigated that same use of IP at Wonderland Sydney. Dreamworld does it, Disney does it, Universal does it, big parks little parks - everyone does it.
Bermuda Triangle didn't close because the all knowing Disney wasn't brought in. They also didn't play a hand in anything structural or anything engineering adjacent. It was already a retrofit of an existing dark ride system (Lassiter's Lost Mine) and it was closed because much like the Looney Tunes River Ride the current management considered money was better spent on new than the huge cost outlays to maintain existing.
Having said that, the cost to maintain those attractions were also so high not because Disney wasn't brought in, but like everything built in that era, virtually no one from the industry at large was brought in. Eureka Mountain Mine Ride, Thunder River Rapids, Viking's Revenge, Looney Tunes River Ride, Bermuda Triangle, Rocky Hollow Log Ride, Dreamworld's Main Street and it's trains/boats etc. etc. etc. were all either built largely in-house or were all out knock-offs of international variants. That "she'll be right/can-do" attitude of doing things a little bit cheaply to try and get something as good as the Americans for a tenth of the cost all but evaporated when Dreamworld's incident happened in 2016, culminating in rides like Scooby Doo literally having walls of theming ripped of, Sky Voyager being re-wired with thicker cabling or Wild West Falls having entire sections rebuilt. There's that old saying of "buy cheap buy twice" and that's definitely been a hard lesson all our parks had to learn.
I think of it as a course correction. There's been pages of discussion here about how parks need to be a solid day's mix of stuff for everyone and it's another hard lesson our parks (specifically Village's parks) had to learn. Skewing each park to a specific demographic doesn't work because at the end of the day, roller-coasters and big new things drive gate (and you don't get that when your park is aimed at three year olds) but having two parks so close to each other with identical rides also isn't a recipe for success either. I think there's some nuance in the middle somewhere that I hope Atlantis (and whatever Movie World builds next) will eventually capitalise upon.