It's not that bad, although indeed Beat is supposed to be some "thug" and whatnot. (he does say "yo" a lot) More often than not the various characters I think add more to the game especally with certain key characters in particular like Kitaniji, Joshua, Hanekoma and to an extent Kariya. The others tend to have their own issues to deal with their own goals within the game so they have their own standout personalities which are obviously meant to not be serious (Higashizawa and his constant food/kitchen references) or being a parody of a certain stereotype (Beat).
And then there is Minamimoto, for whom there are no words to represent his jawesomeness. :P