What about taking both the Fighter and the Barbarian, and transmuting them to Soldier and Warrior?
Soldier has more connotations of formal training, fighting in a group, and fighting defensively. While Warrior has connotations of individualism, more offense, which is fitting for the current Barbarian.
In my opinion, a lot of the problem with martial classes is that "Fighter" is too broad, covers too much of the spectrum. Maybe narrowing the current Fighter a bit will give more room for the other martial classes.