I was holding off on it, but it needs to be said – Surprising as it may be to some, I’ve heard from several gedolei yisroel that exact expression, that he was not a gadol. when i was a teenager and unsure about a lot of things, i asked pointed questions to rabbonim I was close with, one of whom was a gadol beyisroel who said the exact words “he said a sharp vort here and there, but was not from the major leagues”, after saying that he made a moshiach driven campaign to leave behind a legacy in the absence of having children. Later on i learned that many gedolim have said similar things, with the brisker rov saying ,”this meshuganeh thinks he’s moshiach”, or the satmar rov calling him a “shoteh”.
Gedolei yisroel have judged one another before; this isn’t new. Rebbe Evyasar was doubted at first by other amoraim as to his gadol status (מאן לימא לך דרבי אביתר בר סמכא הוא), in gitin 6b. Be was obviously accepted, but there are many other examples where a rabbi is rejected by the composite of gedolim and lomdei torah. These include people like shlomo yehudah rappaport, shmuel Dovid luzzato, the author of me’or aynayim in the time of the maharal(not the chasidish sefer from the heiliger tchernobler), and many others.
There are criteria to be considered a gadol. Tzidkus, torah knowledge, mesorah…a key element is lack of negius. It seems from the behavior of the lubavitcher rebbe that it was in the last element that he was most missing. He was a genius who amassed a lot of knowledge, kept the mitzvos as far as we know, had a mesorah, but seems to have fell prey to the yatzer hora for kovod and gaavah. We see it in the personality cult, the pictures everywhere, the parades, the reformation of chabad into a movement with symbols (the rambam menorah), missionary “shluchim” , the promises of redemption… It points to what my rebbe said about him wanting to leave behind a legacy in the absence of children.