“Rambam and Chasidus was accepted as 100% legit by all Gedolim of subsequent doros. MO was not. “
R’Soloveitchik was very close to R’Kotler z’tz’l, R’Hutner z’tz’l, and the Lubavicher Rebbe z’tz’l even though they disagreed on many matters. R’Kotler even had R’Soloveitchik speak at a fundraising dinner for Chinuch Atzmai. Also notable is that R’Soloveitchik was a member of the Moetzes Gedolei HaTorah of Agudath Israel of America while still in his 30s, before he became a Rosh Yeshiva, while he was still teaching secular philosophy to undergraduates and after he started a co-ed school. So clearly a large segment of the Torah community in America accepted him.
“Helpful, how many doros has it been since R’ Soloveitchik zt”l? 2 or 3? “
Not even one. He was niftar in 1993. Most of his leading talmidim are still teaching at YU or in Israel.
“But one would do well to be sure that s/he is following a live expositor of those shitos, for the reality check value and to have a shaichus to someone IRL. “
This is true for any derech. My rav consistently paskens like Rav Soloveitchik z’tz’l whenever he personally heard a mesorah from him — even when it is a daat yachid.