It looks like this movie is actually distinguishing between different mutations and how they affect the individual. Yes, we saw Rogue dealing with hers, but it was never really discussed much during the first two movies. No mention of how some mutants are gifted with extraordinary powers while others feel cursed with an odd appearance. There is also this idea that all mutants are tolerant toward each other and all mutant-hating humans treat them the same. Ummmm, no. Why do Morlocks live in the sewer? Physical appearance and powers would separate mutants into different categories, just like humans do. It would suck to be an outsider in an already marginalized group. Humans militants might use the rhetoric that all mutants must be destroyed in public, but I bet they really would be jealous of their powers and would try and ally with the human-looking ones to destroy the more freakish of the group. X-Men wants to keep things simple obviously, but experience contradicts it.