Pound's triad of terms implies (for me at least) that one can measure these aspects of poetry quantitatively. This is useful: we can measure how much emphasis the poet has placed on these factors without even asking ourselves how well he or she has done. For example, there could be a very visual poem that ends up being very bad, but we still notice that the poet has tried to include lots of imagery. Ultimately, however, the judgment has to be qualitative.

What I have a problem with is poetry that doesn't seem to offer much of anything in those three basic dimensions. I think of William Stafford: the poet without qualities. (Substitute the name you prefer if you object to my dislike of Stafford, which is almost pathological.)