One of the bigger shifts in criticism, in the 20th century, was the shift away from evaluation as such. That is, you rarely read literary criticism from, say, post-1960, the explicit purpose of which is to establish this or that literary production as "great art." There are standards, of course, but they vary from critic to critic, and they're often beside the point.

What you'll often see instead is praise for some aspect of a work, while the focus of the critical project will be to explain the work by fitting it into some philosophical or cultural context. It's a basic move from evaluation to explanation,
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As I used to tell my classes, after you've said, for instance, that Hamlet is one of the best plays ever written in English (as, in my opinion, it is) what have you really learned about the play? It's about as informative as me telling you my favorite color is blue (which it is). Are now going to attempt to rationally argue me out of that opinion? Of course not. It wasn't an opinion arrived at rationally.

That a play or poem is considered great is a good reason to read it, but it's not a good thesis to pursue in writing about it. There are simply too many conflicting standards of greatness. The better approach, and the more common one these days, is to focus on explication and leave "greatness" as a topic for armchair speculation. And that's as it should be, because "is X great literature" is the least interesting question you can ask about X.

Dave Cheng and I had a good discussion about this question, in the comments on his own answer. I wanted to expand a bit, quoting directly from a comment I made there:

"I could list you out criteria for a great poem, and it would invariably leave out poems I know to be great poems. And, BTW, "Prufrock" is a great poem, one of my favorites. But if I were to look at what makes "Prufrock" great and then try to use that to judge, say, anything by Whitman, whom I also admire, Whitman would suffer greatly. And, if I were to reverse the procedure and derive my principles of "greatness" from a close look at "Song of Myself," Eliot's poem would suffer. Yet I like both, and think they are both great and important works, but not because they conform to any set standard of poetic greatness.

I think, and know from experience, that when people focus on what poems mean, and how they mean, rather than trying to rank them by quality, the conversation becomes a lot more interesting. Because rather than having to defend your heroes and their work, you can focus on the work itself (i.e. what it means and how it functions). And, even if there's wild disagreement on both of those things, it sets stage for productive dialog.

In short, poetry isn't a horse race. It's not about winners and losers. It's about
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Modernist works often included "discontinuous fragments of poetry, fact, image or description, expressing a momentary illumination or beauty, the fragmentary chaos of modern life, a denial of historical or psychological continuity,"

"literary text should be regarded as the expression of the psychology of an individual,

"literary text should be regarded as the expression of the psychology of an individual, which in its turn is the expression of the milieu and the period in which the individual lived, and of the race to which he belonged"
i believe the word "race" is in the context of culture..

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Devices
symbol metaphor concrete abstraction. aliteration enjambment ambiguity

Ezra Pound
What obfuscates ...the crust of dead English, the sediment present in my own available vocabulary ... You can't go round this sort of thing. It takes six or eight years to get educated in one's art, and another ten to get rid of that education. Neither can anyone learn English, one can only learn a series of Englishes.

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Personal commentary

Can we agree on what's beautiful, intelligent? I think so but with some limits. We can apply the golden rule or the science of Fibonacci There are norms for beauty and we often agree on what is ugly. But what does Jazz sound like to a 17th c. ear?

When we look at the linear history of poetry and the eclecticism of post modernism i.e. "everything and the kitchen sink" we see vastly divergent attitudes sensibilities and context consequently it appears that the Socratic method of inquiry is enormously productive as part of the give and take dialectic of poetry in the criticism process
Think of the shock of seeing pure abstract painting circa 1917 produced by The Russian Avant guard

Old salesman's axiom ..Tellin aint sellin

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