I would love to see the train ride enhanced with animatronics, more theming, additional scenery, etc. However, if that is cost prohibitive, here's a thought - perhaps the "History of King's Island" could be told throughout the ride with a recorded audio presentation and signs and historical park photos situated along the route in a timeline fashion.
It would be tough to condense that much history down to a few minutes, but with careful selection of the most significant events I think this would at least make the ride more interesting.