Sounds very interesting. Honestly not trying to be skeptical, the thing it reminds me of was a proposal from a scientist that Australia import elephants and rhinos to help control the spread of gamba grass. Itself imported from africa for grazing, it crowds out local plants, but maybe more pertinent these days, has an increased fire risk profile.

To me the contention with any plan, conservation or otherwise, is "be ultra careful what you bring into Australia".

Certainly not an expert, I'm sure in any case they would be very careful doing any of this, tracking etc. And I don't feel rhino's are quite as aggressive as say, hippos (authorities did not think Escobar's hippos would survive in Colombia; that turned out to be dead wrong). But I would certainly be very curious to see how introducing such a large aggressive herbivore with no natural predators would affect the area, if only because it does seem like a doable task to control the population.