I have an idea, how about at the dead levels (5th, 7th, 11th, 13th, 17th, & 19th) you get the following:
Trained Combatant: At levels 5, 7, 11, 13, 17, & 19 the fighter gets to choose one of the following (no one may be selected more than once):
Knowledge ~ Local becomes a class skill
Heal ~...