It's just 'way too short and uneventful. It doesn't need more lifts and drops, just more meanders, more story, more scenery, more theming.
Funny though ... everyone (including me) seems to think that Popeye's Bilge Rat Barges is a significantly longer ride but apparently it's not, according to different sources that I checked just now. It clocks in around 5 minutes, same as Kali River and Jurassic Park. But the Barge ride seems much longer ... probably because it's at least 3 times more event-filled. Meaning, more gags and more potential soakings.
The lift at Popeye's barges also has a point ... you're being lifted up into some kind of barge-washing machine. Kali's lift has no explanation at all ... gosh ... here's a lift in the middle of this river in the Asian jungle. And here's a burning log right before this ... waterfall. If they tried harder they could come up with something more plausible, such as the lift was built by loggers to move logs from one watershed to another. The drop could be an unforeseen diversion into a sawmill ... your raft hovers within inches of the whirring saw blade until a sudden splash of water or other accident bumps you into the overflow chute ... you have a theme (deforestation) so theme it!
Jurassic Park doesn't feel any longer or shorter than Kali River, but the ride seems more exciting and "worth it" because of the greater interest in looking at dinosaurs and wrecked boats, and the more dangerous-feeling story.