No kids over here
I know things can't always be serious, but you can do comedic relief without it turning into what Bolin does. Think Impulse on Young Justice. They managed to use him to come in and be funny, without him turning into Jar Jar Blinks. Bolin spent the majority on the finale in a battle to save the world, and he was still telling unfunny jokes. I was waiting for his brother to slap him and tell him stop joking for a minute and get his head in the game.
And we'll just have to disagree on the definition of 'balance'. When I think about balance, I think of a scale. A scale isn't balanced until there's 50%ish of the weight evenly spread on both sides. Having the good guys beats the bad guys and take like 90% of the power, and leaving the bad side of the scale with 10% just doesn't seemed balanced. Maybe they should just use a different word.
