Rejection received today as well, the reason given I focused too much on crunch I wanted to share, and not enough on the fluff to engage readers.
"For future submissions, please focus on compelling flavor. It's great if you have a cool mechanical concept, but usually, that idea needs to be secondary to something that's just really interesting to read."
*shrug* I skip 80% of the fluffy bits in dragon articles and go straight to the crunch. I certainly would have had attempted to include interesting to read fluff, I just didn't realize that should be the focus of my pitch, rather than interesting mechanics I sought to share. Seems backwards to my brain (definitely not the way I designed the concepts, I go crunch first), but a legitimate criteria upon reflection.
Ah well, fun to submit...