[Paul_Clayton]

For poetry, I think English has the advantage of Germanic and Latin roots. Such seems to offer some flexibility in tone.

The relative lack of conjugation and declension seems to hurt by constraining word order and reducing opportunities for sound similarity. Of course having rhymes be common also tends to reduce their impact.

Inflection (I think) is part of the cause of extra syllables, so has multiple impacts.

The length itself does seem to add something to the flow/lyricism, but I wonder if there is also a stronger sense of sound whereas English may be more a little more chaotic (not just having multiple roots but borrowing words more often).