Hi Don, interesting points.
R Garfield's guide to what he believes is elsewhere on MM and does make interesting reading, too.
I think for me a good poem is simply the best way of saying something in a minimalist way. I'm no pure minimalist... plenty are more ready to pare but I think if there is much elaboration and fat there then one is in the zone of prose.
Sometimes rhyme / rhythm / metre etc is the best way - haikus frequently are. I often fine form too restrictive to the message, though - but, to repeat, it can be the best way to convey the information.
I (personally) have little interest in elaborate poetry for sound sake. I prefer music for that... then again, my favourite music is plainsong or Tangerine Dream and they aren't exactly Strauss.
All the best, James.