5566 —מי מוסמך לדון בחסידות ובקבלתה

Sivan 5717.

Regarding what you wrote about "Yafutzu Maayanosecha"—some say this refers to all approaches in Chassidus, not just Chabad—broad reasoning and deep understanding in matters of Chassidus is specifically the path of Chabad Chassidus, not of Polin. Those whose approach is to study Torah with explanation and depth, not just by rote, it is understood that this should also apply to the study of Chassidus. See also Heitev HaTamim vol. 2 p. 56 and onward.

Regarding your question about who can give an opinion on whether Chassidus is a received tradition or if the generation can accept it—it is obvious that only someone who is an expert in this field (Chassidus), who has studied it diligently for many years, can rule on this matter. If not, it is entirely irrelevant for him to express an opinion here.

This applies all the more so compared to what the Rosh writes in Bava Kama chapter 4 section 4 (where there the difference is only between someone more accustomed or more meticulous, etc.—how much more so regarding those who do not study this at all. This is clear and simple). See also Kuntres Limud HaChassidus.

Summary

Only those with deep expertise and long-term immersion in Chassidus are qualified to judge its authenticity or suitability for a generation. The intellectual approach of understanding in depth is unique to Chabad, and opinions from outsiders lack authority.