To compare the tier 5's and which ones need help....

Vanguard

Tier Five

Shield Rush: While you have a shield equipped, Activate: Move forward in a line, delivering a shield bash attack to every creature hit. This shield bash does +2/4/6[W] damage. Rank improves cooldown

(100 pts for mobs in a line. meh but ok to gain intial agro and out move the monk... compariable with slayer arrow i guess if you can adrenaline it)

Disorienting Smash: When you shield bash, damaged enemies gain 1 stack of Vulnerability. This can occur at most once every 3/2/1 seconds.
Vulnerability: You take 1% more damage for 3 seconds. This effect stacks up to 20 times, and loses one stack on expiration.

not a fan of vulnerability due to delays in proc. With other weapons/effects it could stack up.

Shield To The Face: +10% chance to make a secondary shield bash.

high in tree when the same was available lower. 10% shield dps? so 10 pts per attack cycle avg?

Armored Strength: +10 Melee Power

Win - 10(100) extra damage per hit(crit)

Defender

Tier Five (30 AP Required)

Reprisal: On Attacked: Your next attack gains +1 damage. This effect stacks (3/6/10) times.

up to 10 pts on next swing - not practical. most i've seen is 3 pts. Too expensive and light damage compared to the other trees. NEEDS ADJUSTMENT

Reinforced Defense: Improves the Armor Class bonuses you receive from shields or armor. Choose the option you didn't choose at Tier 4.

with new light shield was a difference of 7 ac. This equats to 1% less miss chance at level (67% for me to 68%) weak as this should be the defender tree's pinacle of defense boost. NEEDS ADJUSTMENT

Harbored By Light: You gain +10/+15/+25 Physical Resist Rating and Magical Resist Rating. You gain 1/2/3 uses of Lay On Hands.* In addition, while you are actively blocking with a shield, enemies that attack you will take 3d4/4d4/5d4 Light Damage.

I'll give this a meh, doing a bit of help in a few different areas although guard damage would be better than while actively blocking. if it was on hit instead would be thumbs up.

Greater Sacred Defense: Further improves your Sacred Defense stance. Pick the third option left.

+3 damage, +84 hps, or 20% hps depending what you choose earlier. ok but expensive as yet another 3 tier option. weak compared to other trees. I can't see how you can adjust other than change all 3 to a flat 2ap for what tier 3 gives you today. (ie 2ap for 6 str, 6 con or 20% hp)

KOTC

Tier Five (30 AP Required)

Censure Outsiders: Your Censure Demons ability now applies to all Chaotic or Evil outsiders. You also gain 5 Melee Power.

(5% more damage to all attacks! win but less than vanguard's 10 unless your fighting outsiders.)

Vigor of Life: Your Positive Healing Amplification is increased by (5/10)%, and you take (5/10)% less damage from Negative Energy.

same as prior in tree so same as shield bash boost. meh as tier 5 but consistent.

Holy Retribution: Melee Channel Divinity: Executes a powerful holy strike against the target that deals +1/+3/+5[W] damage. On Damage: Evil creatures with less than 1,000 HP have a 50%/75%/100% chance to be forced to make a WIll save (DC 10 + Paladin Level + Charisma Mod) or be destroyed. On a successful save, the affected creature takes 100 holy damage from this attack as well as -6 to all ability scores for ten seconds. (Cooldown: 6 seconds) This ability also recharges one Smite Evil.

give it a thumbs up as a tier 5 attack.

Sealed Life: You are immune to Energy Drain.

useful in a raid?? maybe soon!

Avenging Cleave: "Make a sweeping weapon attack against all nearby enemies for +1(W) damage. Damaged enemies gains one stack of Vulnerability. Shares its cooldown with the Greate Cleave feat. Vulnerability: You take 1% more damage for 3 seconds. This effect stacks up to 20 times, and loses one stack on expiration."

big win (if you don't need power attack/cleave in LD) to save feats.

So in my opinion,

Vanguard gets some consistent dps in additional shield bashing. A situationally useful attack that does ok tier 5 damage. 10% additional damage to all and a 1% vulnerability option. lots of dps. KOTC gets a DPS smite, protection in the new content in energy drain immunity, 5% additional damage, and a 5w attack. Defender gets 1% AC mis chance, a almost useless on hit dps mechanic, continuation of stance benefits which are too expensive, and a shield blocking multi ability buff. (who shield blocks since motd??). Defender is way behind in usefulness to the other trees. It seems that for defender (and stalwart since they are closely modeled) to be appropriate, they need a boost in defense. To keep with the flavor of the tree some AC, dodge or some riposte effect to do damage when missed (or guard effect when hit) with hate gen added in the tier 5 and/or throughout the tree. Otherwise they need some good dps effect or melee power boost to hold aggro. 2-3 damage after you get smacked around on your next swing isn't enough damage boost. At minimum, it needs to be a timer like blitz is on live that ramps up on each hit for 10 sec.