Norben's progression path

Owen commented at our last D&D gathering (roughly paraphrasing): "We need to find a way to make Norben better in melee."  Thanks to a party heavy on ranged combat and light armor, my cleric has become something of a frontline defender and primary AC sponge.  I've been thinking about feat progression on the way towards the E6 endgame feat accumulation stage, whether to focus on offensive, defensive, or spellcasting options.  Here are the obvious primary choices:

Offensive:
Power Attack
Cleave + Great Cleave
Weapon Focus

Defensive:
Heavy Armor Proficiency
Toughness
Combat Expertise
Shield Focus
Saving Shield
Tower Shield Proficiency

Spellcasting:
Alignment Channel
Improved Channel
Turn Undead
Brew Potion
Craft Arms & Armor
Craft Wondrous Item
Scribe Scroll
Craft Wand

There are five major strategies here, or paths of improvement:  Melee buffing, armor/HP, shield buffing, channel buffing, and item creation.  Let's dig a little deeper into, say, a three-feat set:

Melee buffing:  By the time we get three feats we'll be well into level 6, so I think I can make the same assumptions here that I made in my other 6th level class optimizations.  This trio of feats results in a sum of -1 hit and +4 damage on all attacks, and cleaving whenever possible because cleric6 doesn't have a second base attack to worry about losing.

To hit:
+4 BAB
+4 Str (Bull's Strength from 14 to 18)
-2 power attack
+2 weapon
+1 weapon focus
+2 luck (divine favor)
+1 morale (bless)
= 12

Damage:
+4 str
+4 power attack
+2 weapon
+2 luck (divine favor)
= 12

Heavy Mace +12 @ 1d8+12 vs. AC20:  .60(16.5) + .05(.65(33) + .35(16.5)) = 11.26125 DPR
Without those feats:  +13 @ 1d8+8:  .65(12.5) + .05(.70(25) + .30(12.5)) = 9.1875 DPR

Three feats for 2 DPR doesn't seem like a great tradeoff, though it doesn't factor cleave.  If there's an adjacent enemy it becomes 11.26125*1.65 = 18.5810625

Armor/HP:  Let's go full cheese and assume Mithral Fullplate +2.

AC:
10 base
11 armor
2 dex (cat's grace)
3 deflection (shield of faith)
2 dodge (combat reflexes)
4 shield (+2 large shield)
= 32 after making an attack action, 30 otherwise.  Plus 6 bonus HP.

Without feats:
10 base
8 armor (breastplate +2, restricted to medium)
2 dex
3 deflection
4 Shield
= 27.  3-5 AC and a level's worth of HP is kinda big.

Shields:  Kind of boned from some of the more fun shield feats by only having a 10 dex.

AC:
10 base
8 armor
2 dex
3 deflection
7 shield
= 30, and can grant an adjacent ally +2 shield AC as an immediate action.

Armor/Shield hybrid?:  Heavy armor prof, tower shield proficiency, shield focus

AC:
10 base
11 armor
2 dex
3 deflection
7 shield
= 33 at all times, which is +6 AC versus going melee/spell/item routes.  Anyway, approaching 5pm, time to wrap up some work-related things.  Will investigate other feats tomorrow.