In his attempted take-down of Edmund Wilson, which is largely of the "he was a very bad man" variety, Joseph Epstein does say this about Wilson's literary criticism:
As a critic, Edmund Wilson was at his best explaining how literature worked; what seemed to interest him most was the mechanics of creation. He was able to demonstrate why the modernist writers were important by showing precisely how they went about doing things not hitherto done. He was less good, I think, at what Henri Bergson defined as the center of the critic’s task— namely, “developing in thought what artists wanted to suggest emotionally.”
I'm not familiar with the definition by Bergson he cites, but presumably Epstein agrees with it. In that case, the problem with Wilson as Epstein sees it is not a consequence of Wilson's limitations as a critic but with Epstein's own conception of what literary criticism is all about. (If Epstein does not agree with this notion that the critic primarily translates "emotion," then he's merely exploiting it for its value to his broader argument that Wilson was a cold fish, a drunken sot incapable of emotional responses in the first place.)
The literary critic's task is not to meditate on "what artists wanted to suggest emotionally." Insofar as the critic is first of all a reader, he/she does experience the same emotions in reading works of literature as any other reader, but the emotional effects are inevitably particular to, and not detachable from, the reading experience itself. How exactly is it possible to "develop in thought" an emotional suggestion? How could such a "thought" be anything but incomplete and lifeless in comparison to the actual emotion? And why would we need a critic to expatiate on his/her emotional reactions in this way?
If Wilson "was at his best explaining how literature worked," then he was indeed a very successful critic. (I tend to think he was good at this only fitfully, his interest in history otherwise overwhelming his skills as a close reader.) That "[h]e was able to demonstrate why the modernist writers were important by showing precisely how they went about doing things not hitherto done" is highly in his favor, and books like Axel's Castle and The Wound and the Bow remain valuable works of literary criticism precisely because they are descriptive and analytical rather than registers of emotion. So much so that it is puzzling why Epstein has concluded that Wilson's books and essays "no longer fortify me." The two books I have mentioned provide plenty of nutrients if what you are interesed in is literature and not some inchoate sense of "mystery," which, according to Epstein, characterizes the sort of writer--Conrad, Kafka--Wilson could never understand. (Epstein's description of these writers strikes me as willfully reductive.) Take "mystery" far enough and there's simply nothing a critic might say about such writers at all. Everything disappears into mysticism and, yes, "emotion."
Epstein further sketches his idea of the critic's role in the conclusion to this essay, in which he announces that "Critics are not permitted such large margins of stupidity [as are some artists]. It matters that they get things right; their opinions, which is all they chiefly have, are crucial. Wisdom, in a critic, is never excess baggage. . . ." Critics don't just have "opinions." They have informed opinions, which are supported by careful explication of the text at hand. Critics are "wise" if they restrict themselves to this task (recognizing that this is far as "getting things right" goes--there are always other opinions that are just as informed) and do not cast about for "Wisdom" of the more pompous kind. Joseph Epstein apparently wants the literary critics he admires to be sages (anti-Communist and anti-Freudian sages). I'll allow them to be ordinary humans and to direct their attention primarily to the "mechanics of creation."