Generally, I believe in having "a space" outside of the dominant culture as an educational, and essentially curative, step. Before one can use one's own voice to affect change within society, one ideally should be able to hear that voice, to practice using it, without fear of being silenced. Going to a women's college was immensely helpful for me for this reason.
However, I don't think it's productive, as an end goal, to only be able to engage in that separate space and never move outside of it. I think in general feminists believe in engaging the dominant culture, and therefore should invite diverse voices into women's/gender studies--under specific terms (if thou art a member of the dominant cultural group, thou shalt not dominate discussion. Thou shalt deal with listening to the experiences of women, people of color, and working class people, and recognizing their issues and concerns as valid and worthwhile. Etc.). On the other hand, I know that having those (culturally dominant) voices present, in practice, can be difficult; I suppose some would rather just not attempt it, which I feel is unfortunate.