Gluck's poem (which I do like) tells a story through the persona of the grandmother. While this is obviously not a confessional poem (the character may or may not represent the poet's own grandmother - perhaps she made it up). Gluck uses particularly vivid images
"The drugged Long Island summer sun."
"My children have their husband's hands."
She is witty when she alludes to the grandson as a pig, "Squealing in his pen."
Gluck makes a staement with her poem - "I have survived my life." Gluck uses metaphor, simile, language, and son to get a point across. Therefore, the poem becomes a means to an ends. This has historically been one of the purposes of language and poetry. But, there is also a different type of poetry - where the means IS the end.
"Dearest Reader" serves a completely different purpose, if any at all. The title is a bit of a misnomer, Is Palmer "really" speaking to the reader and, if so, what does he mean to tell us? Thre poem is a painting - a scene where "there were trees formed of wire, broad entryways" and so on. Many questions arise that would come up in the typical workshop setting - what is exactly going on here? What is the narrative? Meaning? These questions become obsolete in the poem. The strength of the poem is in it's raw beauty.