Please consider the following changes to the Stalwart Defender tree to help boost pure class fighter tanks a bit.

Toughness: You gain +1 Hit Point for each action point you spend in this tree. Each Stalwart Defender Core Ability you possess (including this one) grants +3% Fortification and a +2% Exception bonus to AC. Abilities are the abilities along the bottom of each Tree, such as this Enhancement.) Antirequisites: Sacred Defender: Holy Bastion.
Overbalance: Your shields gain On Critical: Knock an opponent to the ground.
Reinforced Armor: The Armor Class bonus you gain from armor or docents is increased by [30/60/100]%.
Reinforced Shield: The Armor Class bonus you gain from using a shield is increased by [30/60/100]%.
Tenacious Defense: While wearing medium armor, heavy armor, or wielding a shield and in Stalwart Defense, you gain a +10%/+20%/+30% Competence bonus to maximum hit points.
Replace Reprisal with Child of Earth: Add your constitution modifier as a luck bonus to all saving throws. Does not stack with Divine Grace. (Inspired by the feat with the same name from 3.5 Kingdoms of Kalamar)
Block and Cut: Shield Melee Attack: Performs a melee attack with your main hand weapon that deals +[1/2/3][W]. On Damage: You gain a [10/15/25]% Morale bonus to melee doublestrike for 10 seconds. (Cooldown: 8 seconds.)