The poem as occasioning the question of meaning rather than giving the answer or the meaning itself.
Novels are stories or a work. Poetry, however, offers fewer occasions to be naively read, that is, as simple stories.
Question of meaning comes about from an imaginative stance taken towards a poem, even a syntactically rebellious one, that is primarily linguistic. Not a literal reading, not simply 'messages' or folk-tales in poetry. These tend to be bland anyway.
Meaning (the meaning of a poem) in the sense of signification. Its relation to a wider cultural story. No sense in talk of 'finding' meaning, it was already there.
Musicality of poetry. That 'these words' cannot be replaced by other words. The sense of finding the correct 'fit'. Poetry as a technique that must be mastered, it is not merely playing with words, in the sense that almost anything will do. Far from it, it is akin to building a very complex structure and trying to keep its balance.
Critical practices require more than simply imagination and the poem. A sophisticated critical reading would include many other aspects. The musicality, the cultural context, and so on. Indeed, the critical reading as being a work inspired by the former, in a sense the 'child' to the poetic 'parent' or at least have these connections in a familial manner.