This is based on my view from playing a pure 20 Dwarven Fighter that tanks all raids in the game.
Will only list abilities I think need changing to save space
Core Abilities
Toughness: +1 Hp each point spent in tree and 3% Fort for each Core Ability.
Your most likely going to gain around 40 Hp from this. It would be better being +2 or even +3 Hp per point seeing the amount of damage EE mobs now do and the Hp needed to tank things like EE FoT. 3% Fortification is reasonable netting you 18% (when it is fixed).
Overbalance: 2 AP. Shields gain knockdown on Vorpal.
Has no save from what i see and no timer so mobs stand up straight away. Make it no save knockdown then balance check based on your trip DC to stand up again.
Stalwart Defense: 2 AP. Perma Stance granting 10 PRR & 50% threat. -10% movement speed & immunity to rage. (Requires equipped Shield and Melee Weapon)
Basic Stalwart stance fair enough. Is removed when a throwing weapon or scrol/wand is equipped. This needs changing since range is a crucial part in tanking Raids such as LoB and FoT aswell as stopping UMD toons.
Standfast: 2 AP. 30 Second Action Boost: granting +20 save vs fear and knockdown, removes those effects if used whilst feared or knockeddown.
Will rarely be used especially seeing as it locks you out of other action boosts with the timer. At least make it a seprate cooldown.
Last Stand: 2 AP. 30 Second Action Boost: +100% maximum hp, 50 PRR, on attacked healed for 1d10 positive (effected by H-Amp). 3 min cooldown
Seeing as this is a capstone. Having another Action Boost feels rather lackluster. I would rather it be a permanent 20% HP, 20 PRR and 1d2 positive heal.
Stalwart Defense Line
Improved Stalwart Defense: 3 Sub catagories that improve your Stalwart Defense Stance. 2 AP each tier.
Durable Defense: +[5/10/15] Competence to PRR.
Inciting Defense: +[25/50/75]% Competence melee threat gen.
Resilient Defense: +[1/2/3] Competence to all saves.
Costing 2 AP for each tier is too expensive. Especially seeing as this line has 6 stages to it and to have 3 tiers in later stages requires 3 tiers in all stages before it.
Greater Stalwart Defense: 3 Sub catagories that improve your Stalwart Defense Stance. 2 AP each tier.
Hardy Defense: +[2/4/6] Competence to Con
Strong Defense: + [2/4/6] Competence to Str
Tenacious Defense +[10/15/20]% maximum Hp
Again Costing 2 AP each tier is too expensve. Especially seeing as 3 stages to this line following on from Improved Stalwart Defense. And diminishing returns on Tenacious defense only gaining 5% hp after the 1st tier for the same amount of AP sucks.
Other
Threatening Countenance: 1 AP. [1/2/3]Haggle, [1/2/3] Intimidate & [5/10/15]% melee threat.
Make it [2/4/6] so as we can gain a resonable boost to intimidate at least and could even do with [10/20/30] for those that want to tank without using a shield.
Instinctive Defense: 1 AP. Take [5/10/15]% less additional damage whilst helpless.
At least make it [10/20/30] and people might consider it. At the moment its a waste of AP.
Counter Attack: 2 AP. 30 Second Action Boost. If you are attacked whilst blocking your next attack within 3 seconds gains +[1/2/3][W].
This ability really sucks as an action boost. Blocking is used as a response to something. People won't hit a boost then think ooo lets block so as to do more damage. It should be a permanent ability that costs 1 AP per tier otherwise it will never be used.
Block and Cut: 1 AP. Melee Attack dealing +[1/2/3][W] and on damage [10/15/25]% Double strike for 10 seconds. 20 second Cooldown.
Personally i would prefer to just have a permanent [5/10/15]% Double strike whilst using a shield.
Shield Expertise: 2 AP. Your Shield gains +[1/2/3] Enhancement Bonus.
2 AP for 1 AC is rather expensive. Base abilities in the tree grant +1 AC and +1 MDB for 2 AP. With the amount of pre reqs required it would be better as [2/4/6] AC for 1 AP.
Armour Expertise: 2 AP. Your Armour gains +[1/2/3] Enhancement Bonus.
Same problems as Shield Expertise.
Whats missing
With a few of the abilities being Action Boost based there are no Enhancemens for extra boosts. Although if changes are made and some of the boost abilities made permanent as i suggested this wont really be a problem.
There is nothing to improve Combat Expertise. Seeing as this feat is not widely used. A Enhancement granting [5/10/15]% extra AC for 1 AP would be welcome. This would bring CE up to 25%.