sechel, things like that are why I am adamantly opposed to chassidus in general. Torah was given at Har Sinai to the entire nation. One of the reasons was that so nobody could deny it. The Besht’s teachings represented a radical change from traditional Judaism. So why were they “revealed” to him and him alone? He claimed he ascended to the Heavens and learned with Achiya haShiloni. Do we have records of anyone else ever doing such a thing? Tanaim? Amoraim? No, we don’t. So why would the Besht be able to do such a thing?
BTW, you took that line out of context. Here is the full text of the letter that the Besht wrote:
“I asked the Messiah: When will you come? And he answered me: Hereby you will know, when your teachings will become known and revealed in the world, and your wellsprings will burst forth to the furthest extreme, that which I taught you and you comprehended, and they too will be able to engage in unifications and elevations as you can, and then all the husks will be removed, and it will be a time of favor and salvation. And I wondered about this, and I was greatly distressed about the great length of time: When can this be? But what I learned when I was there is three charms and three holy names. They are easily learned and explained. And I thought: It is possible that with this people my age will also be able to reach a level like mine.”