One trend I have noticed so far with characters is that those with more tame abilities seem to be those that can much more easily blend with society. Some of the more potent abilities, like the Ratman or Taylor's, come on characters that do not have that option. I'm not sure if that was intentional, but I feel it makes sense. If you like that pattern, you might continue it as well. It's just an idea, though. I don't think it's a rule anywhere.