Yes it is a deliberate pun on rainbow, for that very same reason. Also, an allusion to a pet name for his middle name, Beuregard. The Reign comes from his Authority ability to command and rule over others, while rainbow refers to the fact that his bolt attacks are a prismatic light, instead of one solid color. As for the drawbacks, I debated using a continuous power, but I forgot to check the tricks and augments I had available to see if anything was appropriate. If I find something I like, then I'll exceed the drawback limitation. All in all, I'm excited for this one, and I've decided that Alistair Beuregard Carver will be my first Amp character.