Plot devices, you know. If the plot needs someone who's superstrong and agreeable enough to help the heroine, I can't, obviously, declare that the plot is wrong. Sometimes a crafty solution is possible -- there are some incidents where I was able to figure out how a randomly generated character saved the plot issue -- but that may focus more attention on something incidental than is wise.
But perhaps I could give them secondary powers that are random. Which would definitely help. (Heck, one of those could use a primary power and his plot device ability as a secondary power.) And even help with the world, 'cause while someone could probably draw a connection between any power and any given personality, it would be a bit more interesting to connect invisibility and ability to communicate with birds.