I suspect if Niven's "SOft Weapon" had been adapted for a theoretical 4th season live action episode, to reduce costs, Klingons or some other human(oid) warrior race would have replaced the Kzinti. After all, Spock was slipped into the role of Nessus, a supposedly pascifist plant eater who manages to humiliate a predator species alpha male. It would not have been so great a stretch to take it one step further, applying the Kzinti sensilibities to another pre-existing Trek species, like, well, the Klingons.