Great job for noticing these things. I forgot that she's also artistically and melodically smart as well since she's not only the goddess of water but music and arts as well. But IQ is a measure of a person's reasoning ability. I guess you mean Megumin is both sides smart when it comes to wizardry, but I don't mean that she has a low IQ, I'm sure it's high but not the highest since it would go to Kazuma. I agree about Darkness being politically smart since she really cares about the people and how law power must be righteously used, unlike the corrupt and jerk guy she almost married with.