Something that had passed me by, until it was pointed out to me, was the interview with Kevin Grevioux from a few months ago that answers the question I was asking about a lot of the characters in New Warriors. Notably, why Stacy X, Beak and Angel aren't physically closer to how they appeared after M Day. Something I know I and others have questioned. I mean, what DID happen to Barnell's big nose and Stacy X's snakeskin. Well, I guess my guess that Stacy might have shedded wasn't too far from the truth. Grevioux explains his thinking behind the changes:
IGN: The last character I want to address is Beak. Why did you choose Beak to be a member of the team, and is there any specific reason why he's portrayed so handsomely compared to his former bird-like appearance?
Grevioux: Yeah, the mutation that made him what he was caused him to appear bird-like. When he lost his mutant abilities, the way I look at it, it happened slowly with him. In other words, when Scarlet Witch did what she did, his mutation went away immediately, but his body still changed until it settled on what it is now. In my mind this is how he looked prior to his slow-change into the Beak character, or what became Beak.
Which explains that. Seems like Grevioux's thought about the question of why some mutants retained physical characteristics and others didn't and some now look entirely different. Which is more than anyone else at Marvel did. So, presumably, other mutants who retained physical characteristics of their mutations were/are slowly changing back. While other mutants like Marrow, Chamber and Blob retained physical signs of their mutation, presumably that's because their bodies were permanently damaged by their mutations, rather than it being a natural change. Presumably with mutants like Jay Guthrie, if he WAS depowered by M-Day, as seemed to be the case, his wings would have disappeared over time.
Hmm. Glad I'm not the only one who totally overthinks this stuff.