Benefit: Once per encounter when you declare you are fighting defensively or taking the total defense action, you may enter a defensive stance... Your defensive stance is initially usable only once per day. You gain an additional daily use at watchful fighter level 4th, and every four levels thereafter.
This doesn't make sense, is it per encounter or per day?

Weapon Master: The stunt gladiator, the exotic weapon specialist, the soldier who practices endlessly to perfect his technique. These and other weapon master fighter archetypes emphasize technique above all else. A weapon master fighter gains Balance, Concentration, Iaijutsu Focus, and Sense Motive as class skills, and gains Weapon Focus (with a weapon of your choice) as a bonus feat. A weapon master fighter also gains proficiency with a single exotic weapon, armor, or shield of his choice.
This doesn't mention which skills are important to the class.

I just saw two small things that I thought you should know about. Otherwise, I love you're work on the fighting classes, keep it up!