@ CS
“Gerrer Rebbe, Baba Sali and reb zusia for example weren’t involved with writing halacha (as far as I know) and were still seen as tzaddikim..This shows that the criterion here is not a specific list – just he is known and trusted to Torah true Jews by his behaviour etc.
This is true. Another example would be the Ramchal, we don’t have Halachic works from him. One could even point out that there was a strong opposition to him by other leading sages during his lifetime (a cherem on certain works even).
You are right that the list of 3 criteria wasn’t meant as a check list per se, it’s not that you need “all of the above” and davka these 3. You asked me what I would consider objective criteria for determining who is a Gadol and I gave 3 examples. However what they have in common is not “he is known and trusted to Torah true Jews by his behaviour etc”. Rather the common denominator is the seriousness with which other Rabbonim take his Torah.
Next point
“Also yes Torah true adherents add value. We see that ain melech blo am, and the Kings of today are the Rabbonim and Torah leaders. If someone tells you so and so is a Rebbe and he has two chassidim, you will think less of him than a Rebbe who has a thousand, because the fact that a thousand Torah true yidden have chosen him to inspire and guide their Avodas Hashem gives him more credence.”
The ARI HaKadosh, The RMCH”L, the GR”A and the BSH”T had a small number of direct Talmidim. No one considers them less of a Rebbe because of this.
Next Point
“And lastly by learning their Torah we see what kind of person or Torah great they were. Like the Or Hachaim for example”
Not necessarily. The learner has to be competent to evaluate.