As a former VB employee, the strange demolition permits set in the Volcano made sense to take out Tai Nui. There were too many "spinals", where the ride's g-force acceleration at the bottom would result in guests complaining of neck injuries. This was well before my time but supposedly the ride went down for refurb maybe a year after its initial closure and they had replaced some of the track segments but the issue still persisted. Now, the water runs just to make sure it doesn't fall apart. I doubt they'll add something new there because it would just have to be the same tracking but I'm assuming it'll happen during that refurb period.