Does the poem give you any emotional impact?
Poems are usually written to evoke a reaction from the reader. The reader, of course, must be willing and able to have a reaction. In other words, the poem may be about a breakup and intended to make you feel sad. You may instead think the lover got what he deserved for being such a jerk, which is a legitimate reaction. In your essay you may point out where the poet lost your empathy, but you must also identify what devices (onomatopoeia, caesuras, whatever) were used to convey the poet's intended emotions. THEN you may say that in spite of the alliterative swooshing waves and whispering forests, you doubted the lover's despondency based on his repeated infidelities cited in the second stanza.
Some poems are less obvious about the emotion being called on. A mild meloncholy may be harder to detect than wild despair. Irony may disguise anger with humor. Look for the poet's meaning, identify the ways he/she conveys that meaning, and describe your reaction.
Of course it does. A poet diverts his emotions towards the reader, if that happens in the best way, means, if any poet is able to make the reader feel what he felt, then that is a succesful poem. In other way, the moods may also be shifted to the reader, for example any meloncholic poem would make us feel sad. Success is rated by how far the poet could attract his reader to his work. So there's an emotional impact in a successful poem.