The alder tree
shrivelled by the salt wind
has lived so long
it has carried and sheltered
its own weight
Ewen McCaig (editor), The Poems of Norman MacCaig (Polygon 2009).
There is something to be said for brevity and directness (bearing in mind that they do not preclude depth and implication and suggestiveness). The Chinese and Japanese poets come to mind. In fact, "Old Poet" sounds as though it could have been written by, say, Wang Wei or Ryokan. We should also remember, for example, that Edward Thomas wrote a number of fine four-line and eight-line poems.
Thom Gunn, in an excellent essay on the poetry of Thomas Hardy, makes an observation that merits thinking about in connection with brevity and directness. Gunn notes approvingly the absence of "rhetoric" in Hardy's poetry, contrasting it with "the strain of all that rhetorical striving" in Yeats's poetry. Gunn writes: "Rhetoric is a form of pretence, of making something appear bigger or more important than you know it is." Thom Gunn, "Hardy and the Ballads," The Occasions of Poetry (North Point Press 1985), pages 104-105.
As one might expect, poems that are brief and direct tend to be short on rhetoric. "Old Poet" is, I think, a wonderful example of a great deal being accomplished in a small space, without rhetoric.