Popa,
In regards to point 4, I suspect that what R’Lichtenstein would tell you is that the Yetzer Hara today, through media and secular education, is much more prevalent and powerful and therefore a greater level of Torah is necessary for women to withstand it.
In this vain, I once heard argument made by a woman who was bothered by the materialism and shallowness of the girls in a local Modern Orthodox school and thought that making Gemara and more intensive halacha mandatory for girls would help solve the problem.