Barthes, Benjamin: Minor/Major?

My colleague Mark Greif, one of the editors of n + 1, has a brilliant and incisive article on Susan Sontag in the current London Review of Books, which--a rare phenomenon for work on a figure who usually evokes such polarized reactions--treats Sontag judiciously and thoughtfully values her strengths and weaknesses. One point of interest is Greif's assertion that Sontag seldom wrote on major thinkers; I take, and accept, his general drift, but wonder if Roland Barthes and Walter Benjamin, on whom Sontag wrote extensively and indeed were, in the middle-to-late portion of her career, virtually adopted by her as her signature thinkers, are exceptions. Admittedly, neither are systematic; but both in terms of their influence and the breadth of their work--which in each case ranges across fields, disciplines, national literatures, proprietary discourses, might be said to make an exception in their case. Also, I am interested--in the wake of my recently completed book on theory--on Barthes and Benjamin as figures of the middle ground, people who do not usually or typically evoke the fiery reactions that Derrida and Foucault often inspire. Does their lack of system, their epistemic modesty, their aphoristic, staccato mien, make them more beloved? Do they seem more literary, less philosophical? Would the people who find Derrida and Foucault so indigestible have felt the same about Kant and Schiller in their own, as-yet-undomesticated day?