Explain what is broken with the fighter. Do you want him to be more interesting in combat? or in role-playing? or in interaction? What?
If you run a hack and slash campaign, the fighter is great with his number of attack increasing and his feats to give more damage. If you are role-playing, there are people who are nothing more than their jobs and want to drink versus those who actually have other skills and talents. If you make only a combat monster in a campaign of skillful characters, you will lack interest. Buy a few knowledge skills and be the expert in the know or get social skills. If you lack the skills to play, give an interesting backstory to have something interesting to do or try to do.