Jar-Jar is a screw up, he's the biggest screw up of the Gungan race, but it does work into one of the themes of the Star Wars flicks, that the smallest person (Luke, some random Ewok, Anakin Skywalker being the only human that can race pods) can have the biggest effect on the galaxy. But Jar-Jar does it by still screwing up it. He even takes out a battle droid tank on his own, by awkwardly juggling it and hitting the driver completely by accident. I see him less as a slapstick character but more of a wry ironic way. He's bad at life but he manages to win anyway, mostly because he stumbles his way into heroism.