You can carry your discussion on that with brother psyah and Ibn saddique. They are more knowledgable on that. I have a different approach.once i agree that the person making this new claim that majority have not claimed in the past desrves that position and for that i should first know the credentials of that person . See this is where our discussion reaches to point of no return, a dead end. If we are to really find the haq then why not enlighten us with the personality.Why keep us in dark if mehdi is here. Tell us more about him , his mujadidiyat inshallah then it will be much easier to reach the truth.
Sorry if my odd man out example offended you. Maazrat dost.