What defines poetry through the ages

I was listening to someone talking about Biblical poetry a little while ago, and took umbrage to them describing it as primitive. I don't think it's primitive, it's just different. To us poetry features, generally, rhyme or metre or both, but to other cultures it is otherwise. Biblical poets went for parallelism. Norse or Old English poets went for half-lines and a formal system of alliteration. Would either of those not have looked at poetry from our culture, and deemed it "primitive", because it lacked what they valued in poetry? Or would they have said, "This is cool; it makes the poetry better"? I fancy more the former, given what Milton, who wrote without rhyme, had to say about it, in his preface to "Paradise Lost" (which I should add I have not read):

The Measure is English Heroic Verse without Rime, as that of Homer in Greek, and of Virgil in Latin; Rime being no necessary Adjunct or true Ornament of Poem or good Verse, in longer Works especially, but the Invention of a barbarous Age, to set off wretched matter and lame Meeter; grac't indeed since by the use of some famous modern Poets, carried away by Custom, but much to thir own vexation, hindrance, and constraint to express many things otherwise, and for the most part worse then else they would have exprest them. Not without cause therefore some both Italian, and Spanish Poets of prime note have rejected Rhime both in longer and shorter Works, as have also long since our best English Tragedies, as a thing of itself, to all judicious ears, triveal, and of no true musical delight; which consists onely in apt Numbers, fit quantity of Syllables, and the sense variously drawn out from one Verse into another, not in the jingling sound of like endings, a fault avoyded by the learned Ancients both in Poetry and all good Oratory. This neglect then of Rhime so little is to be taken for a defect, though it may seem so perhaps to vulgar Readers, that it rather is to be esteem'd an example set, the first in English, of ancient liberty recover'd to heroic Poem from the troublesom and modern bondage of Rimeing.

Thoughts, anyone?