You can make a good case for poetry being "difficult" or "complex" to assess: metaphoric aptness and accuracy; imagistic surprise; emotional layering; musical patterning; allusions. And on and on ....
Elementally, though, poetry is individual words, one after the other. It's easy to assess and categorize words. Whereas Patricia Young's "More Watery Still" is filled with concrete nouns ("huckleberries", "pipe", "knapsack", "butterflies"), Susan McCaslin's At The Mercy Seat is bogged down in abstract nouns and intransitive verbs ("mood", "listening", "intends", "thought", "strictures", "will", "become", "nobody", "speech", "silence", "world", "try", all from the volume's one page opener: "White Meditation").
It seems to be par for the course that poetry beclouded in abstractions tends to go in for soft moralising. This book is no exception, and the above-mentioned poem ends with the expected mild lozenge: "When the world speaks/try not to get in the way."
Of course, abstractions are often necessary. It's the degree and appropriateness that matter. A poem saturated in concrete detail can be very affecting with a distancing overview, sometimes ambivalent to what's just been experienced by the writer and reader (I'm thinking of some of Ken Babstock's fine philosophical conclusions or suggestions which come out of the experience, rather than being pasted on to a previous bromide).
Not surprisingly, McCaslin's best efforts avoid the unsensed word choices. "Fistfalls of Dark in the Suburbs" has a lyrical quality lacking in much of the rest of the book; I could experience its content AND rhythm, and though the "your" addressee was still a bit simplistic, the mood and emotion at least flowed, with conviction, from the event, not the disembodied lecture.