R’ Yitzchok Scheiner & R’ Elya Weintraub who are both American born Gedolim living in Eretz Yisroel both signed the ban against his books & they obviously read English as well as me & you.
R’ Moshe Meiselman (who has a Phd) gave a shmuess in Toras Moshe calling the books kefira.
Excerpts from the books were read to R’ Moshe Schapiro by a Slifkin SUPPORTER & after hearing those words he also gave a shuir calling it kefira.
R’ Aharon Feldman (who initially was a Slifkin supporter) wrote a series of articles explaining why R’ Elyashiv & all the Gedolim hold that his opinions are kefira.