"Metrical Feet" is a poem about different types of poetic meter, but it is also partly about the skills Coleridge felt were necessary to become a poet. So on the one hand, the poem teaches us about the basic metrical feet, and the different feelings they give a line of poetry. And on the other hand, it tells us what skills we need as aspiring poets. And these skills aren't necessarily what we might think, or at least not entirely. They include "sound sense," but also things like "tender warmth." The second stanza in particular tells us what we need to be famous poets in English culture; Coleridge was pretty famous, so you can bet it's good advice.
The speaker suggests that being a successful artist or poet is as much about one's feelings and personality as it is about knowledge.
"Metrical feet" destroys the art it's trying to perform. It's way too meta.