Does the poem "The Rime of Ancient Mariner" seem ahead of its time, or does it seem quaint and old-fashioned?

This question was one that William Wordsworth and Samuel Taylor Coleridge had to grapple with when they collaborated on their collection of poems, "Lyrical Ballads." When introducing their work, they had in mind a "new" style of poetry, the lyrical ballad, that abandoned some of the conventions of traditional verse in that its subject matter focused on the common man or childhood and avoided the elevated diction that had been typical of poetry--such as abundant personification of abstract ideas and drawing excessively on mythological and historical allusions. They also wanted poems that captured a high degree of emotion. Although Wordsworth had collaborated with Coleridge on "The Rime of the Ancient Mariner," Wordsworth had mixed feelings about whether it belonged with the other poems in the volume they were releasing. In the end he agreed to put it in, but he felt it was different from the type of poems that comprised the rest of the collection. In the second printing, he again had to decide whether it belonged. After much consideration, he retained it because of its "passion" and because of the sheer beauty of its imagery and language.

Coleridge did not seem to be especially committed to the "new" style of poetry, at least when it came to this poem. In fact, in a later printing, he went so far as to add the "glosses," the marginal notes that make it seem as if an old-fashioned pedagogue were commenting on the action of the poem as it plays out. Certainly these glosses do nothing to help the poem feel like a new or cutting edge style of poetry; in fact, they make it feel antiquated. This ancient feeling gives the poem an extra layer of charm for some readers. Still, the poem did meet some of the requirements that Wordsworth had laid out for "lyrical ballads," especially in that the poem featured a common man as the main character (the mariner), that it used simple language rather than elevated diction, and that it portrayed intense emotions. Beyond that, the sheer beauty of the poem's imagery and musicality are timeless. 

"The Rime of the Ancient Mariner" is a curious hybrid of the new and old even while the beauty of its language is timeless.