Y'all ain't even know how to speak slang, the hell you think we is, some kinda' thugs!?
Yo Phones, let's fly, this ain't no place ta' crash.
Nope, still sounds bad and unrealistic to me <_<
If you noticed, all of the characters have different personalities. Seifer was designed to seem like a thug in the beginning of II, Beat was designed to use slang for a more interesting male character than a brooding Neku and a sarcastic (but lovable) Joshua. And I doubt they think they're "bad-ass", if you remember, these are the same people who yelled "Roxas JUMP!!!" and ripped their pants. Would you rather have a Sora-clone or a different character?
One of them yelled "Roxas JUMP!!!" while some of the others think they're ghetto-hipsters apparently <_<