The answer to improving Kali is Tiger River. As stated no amount of added scenery can correct the ride's short length or make it feel like a disappointment next to the Tiger River concept. Kali isn't an ugly ride and already has appropriate scenery for what they were going for, there's just not enough room to improve it without making it larger. It needs the blessing of size (and budget/ambition). Here for example should outline the problem-
They'd basically have to rebuild the ride from scratch to get it in order. Make it a lengthy water safari going alongside actual animal exhibits as originally intended. The disorienting ride system in Kali also makes enjoying scenery hard as well. Tiger River used more raft-like boats rather than the generic circular boats currently used. It is also said that the ending of the ride would still have utilized a rapids segment with some drops for a big finish. Sounded like a good idea to me.