The tweek was small, really, basically the replacement of one particular haiku in a haiku sequence. It's always interesting how much such an edit can sometimes really improve things. Not only did I get the revision past David, I actually like it a lot better myself and am much happier with the final resulting poem.
So, I now have two poems in the wings at Dreams and Nightmares - a haibun and a haiku sequence.
Now, if I could only get Asimov's to accept something of mine, I'd be a happy camper.