Ummm... that would, at least, be a definition. Though I suspect it is one that isn't strictly ahered to by those who write 'non-rhyming poetry' and I suspect many such poets would disagree with it.

For me poetry will be the rhyming stuff - there's a real art to it (and like you say, a bit of a game) and when someone gets it right it provides some of the best forms of expression we know.