Divine Vigour does NOT require Extra Turnip!!!
I'd make your stat array something like this:
Str - 15; Dex - 14; Con 14; Int - 10; Wis - 12; Chr - 16
After the tweaking I realize this is virtually the same as yours however I would favour Chr over Str because of the increase in saves, smite stuff, turn attempts and god-damn good looks!!!
Now to the feats, (and I can only count 10 that you get so I'm obviously missing something)......
You need the reqs for VoB so:
Sacred Vow
Vow of Obedience
The others however:
Power Attack.
Sanctify Martial Strike.
Weapon Focus (Greatsword).
Improved Critical (Greatsword).
Resounding Blow.
Quell the Profane.
Divine Vigour.
Improved Buckler Defence.
Divine Shield, (if you do get an 11th feat from somewhere).
Now my reasoning behind my further ammendments are as follows.....
Great Cleave - IMO a useless feat and if you're fighting critters that let you make use of this then A. they're not relly a threat to you and you can take your time, or/and B. get your resident spellcaster to fireball/lightning bolt them.
Cleave - Only slightly better and it only works if you're the one to finish off the 1st creature and not one of the rest of the party which happens a LOT IME!!!

You also happen to have to have another creature within striking distance which also happens to not always be the case making this feat not terribly worth it.
As IC said, with re to RB & QtP, you always fail on a one. Just check out what cowering does to anything and you'll agree that effectively nullifying its next round of actions is an IMMENSE ability, (plus you can also hit it a lot easier). Now since you're a dragon slayer I reckon your party is going to appreciate that ever happening when you come up against one of the scaly bastards!!! Then there's the Str loss with QtP and since you'll be the one toeing to toeing with the melee critters.....nuff said. These two are obviously made SO much better with the feat Improved Critical, (personally though I'd apply the Keen enhancement to your blade and free up space for yet another feat!!!).
Improved Buckler Defence & Divine Shield, need I say any more? Of course I don't but I will. More AC and LOTS of it, which should last an encounter. With your loot, purchase a +3 buckler which should be very reasonable and which gives you +4AC. You already have a +3 Chr bonus so why not up that to +6 with the relevant cloak of charisma and Bahamut be praised, you have +10AC for X rounds!!!!
So all that's left is your equipment and I can't be arsed to go into that in depth but here are my recommendations if you can afford it.
1. +1 Adamantine, Keen Greatsword.
2. +3 Buckler of some description, (possibly Adamantine if that can be of use).
3. Cloak of Chr + preferrably 6.
4. Gloves of Dexterity + preferrably 4, (maxes out armour potential).
5. Boots of Flying, (believe me, they rock).
6. Ring of Free Action.
7. Belt of Major Displacement.
Good luck and may Bahamuts blessings go with you.
Slight edit.....having a Dex of 10 could up that Str and Chr to silly levels without damaging you too much, just remember an application to Chr will counteract the Ref save loss, AND AC loss, (when Divine Shield is up), and who cares about the initiative anyway?