IMHO a class is a toolkit, not a straitjacket.
A Rogue may be a charming diplomat who is fat and clumsy, and who cannot sneak around. Or he may be an acrobat who can't talk to save his life. Both are valid uses for the class.
The characterization write-ups are intended to inspire players. IMHO they're NOT intended to limit players.
So like, if it's your first character, and you're new to this D&D thing, and for whatever reason you're playing a Warblade, then that section gives you a decent default outline of how to have fun with the class. But when Conan the Warbladebarian the Third dies ("stupid snake-priests"), and you're on your fourth Warblade, maybe you feel like not playing the exact same cookie-cutter character again. So, you use the tool in some other way. And that's great.