I'll grant Gene as the weakest of the kids but I still think he's pretty great. (And I like him better than Linda, though she's really grown on me since the beginning of the show; she's gone from being standard nagging sitcom wife to being just as delightfully batshit as everyone else.)
I like that each kid is a different kind of crazy. Tina was originally written as a boy and it shows in her weird combination of teenage-boy and teenage-girl sitcom tropes -- she's got the adolescent sexual frustration, confusion, and aggression that you typically see in teenage boys on TV, combined with the shyness of the unpopular-girl archetype. There's a combination of charming naivete and eyebrow-raising kink there and you never know which you're going to get.
Louise is the most cartoonish character on the show and liable to say absolutely anything. The sugar-rush of a child mixed with the comedy of children saying things that are wildly out-of-character for a child to be saying. Tina's probably the most relatable of the kids (and given the paragraph above I don't know what that says about me), while Louise is Daffy Duck. (Earlier, "Woo-hoo, woo-hoo!" Daffy.)
Gene's kinda got a combination of Tina's adolescent cluelessness and Louise's aggressive confidence. Where Tina mumbles oddball things, Gene shouts them. It's a good approach to contrast the two characters -- the reason Tina was changed to a girl was that she was deemed too similar to Gene; it's not just the gender change that helped to set the two of them apart, it's the completely different demeanor and delivery of the two actors.
And I'm STILL laughing at last week's "Bleth this Meth".
