It would also be epic if he never really died. Lets just say that you are right and KK is not Jiraiya. He would just be a Jiraiya clone and less interesting. C'mon now the white hair, fire style, fights with toads, toad eyes, rasengan rasengan rasengan he effing knows rasenga. Jiraiya is the best theory out there right now.He's not Jiraiya, Jiraiya can't be alive. However, he could be someone related to him like his long lost son or something.
Jiraiya's death is the most epic one in Naruto verse, topping even Minato/Kushina and Itachi's deaths. They can't ruin it like that.