The psak of R’Elyashiv, that kabolas “ol mitzvos” is required is not novel, but nor is it in contradiction of R’Druckman’s conversions. “Ol mitzvos” means accepting that the yoke or the burden of mitzvos, meaning accepting that they BINDING. It is not equivalent to being m’kabel to DO all the mitzvos. One can be m’kabel the “ol mitvos” without expecting to keep them or even knowing what they are.
I am sure the author meant well, but he was clearly getting his information from only one side on this issue.
The accepted practice in klal yisroel for centuries has been that if the Bais Din was a proper Bais Din, if the Rav was a proper Orthodox Rav, the kabolas mitzvos is presumed valid and the convert is a full fledged Jew!