You know what, I am actually going to stand up and support Palmer. Yes, he is a fat moron with a serious case of ADD, yes he gets hit by a truck. But look at this, he takes a TON of damage. He takes more damage than most bosses up to this point, meaning he is harder to kill than JENOVA, giant spiderant things, giant robots, and the zombie that nearly destroyed Red XIII's home.
And then, after being pounded on the party and mocking them constantly during the battle, he just merrily skips away, gets hit by a semi, and still survives. Either the party is a lot weaker than we think, or Palmer is one of the toughest guys on the planet. If he were more physically fit, he could probably replace cait sith, and be less annoying (however slightly) in the process.