Kids are smarter in the 24th century. Federation kids start schooling at somewhere around two, if you believe the Primary Care classrooms on the Enterprise D. And Jake Sisko is the least 20th-century-like of all the characters on DS9. With the exception of an affinity for baseball, he's as unlike a 20th-century sitcom character as can be. They worked really hard at that "We're a Different Culture, Damnit" thing on DS9, probably a lot harder than the others, mostly because there was so much political storytelling and there were a few dozen humans surrounded by aliens in an alien setting, so distinguishing the human culture from the surrounding one was important. I loved Jake. Jake needs more show. ;)
The DS9 characters were also the least Americanized humans of all the trek shows. Which I think was important given that the first "World Government" Earth had (which was only really referenced once, I think in Next Gen) was obviously *not* centred on the U.S., whether or not Zephram Cochrane was an American, or close to, and First Contact happened in... Wyoming? Montana? Somewhere in the middle. The Federation is not an American instrument. It is, in fact, thoroughly, albeit somewhat naively, socialist. No money, no poverty, everyone at least on Earth guided to do what they want to do and are best at doing, and never mind utilitarianism.
Although to watch Enterprise, you'd never know it. They are *very* 20th-century, which is one of the many, many things about ENT that bugs the crap out of me.
I really, really want more Trek in the 24th century. Gimme. >.