Beating Batman: Sir Giacomo's Guide to Monks

[Sir Giacomo]

6d8 averages out to 27 damage.

Actually, a Fighter with a +4 Greatsword, some of the Weapon Specialization feats (+2, +4), and 25 Str(18 base +3 level increase + 4 item) deals 4+2+4+7*1.5=20.5 damage
His greatsword is a 2d6 weapon, so that's an additional 2*3.5 damage right there.
An unenlarged fighter, therefore, does 27.5 damage easily.

If enlarged like your monk he gets an additional d6 to weapon damage, and +2 to strength.
This results in and additional 3.5 + 1.5 = 5 points of damage. 32.5 points of damage total.

First of all, the 1.5 multiplyer only applies to the STR, not the spc. or enhance bonus. The fighter with a TH-weapon will add 1.5 of his STR bonus to the damage.
So at level 15, enlarged, he'll do:
3d6 (base) + 12 (STR bonus damage) + 4 (enhance) +4 (wp. specialisation) = 31 avg

Well, since you added the STR bonus to it, a monk specialised in damage-dealing will have a STR of exactly the same extent (note that your STR item AND the +4 weapon are more expensive than the monk's expense for monk's belt and divine power - to make up the monk adds a lvl 3 pearl of power and rod of lesser extend to receive a +3 enhancement bonus from greater magic weapon casting for 24 hours); plus the monk gets +6 enhancement vs the fighter's +4, so actually he has higher STR than the fighter).

6d8 (base) + 9 (STR bonus damage) +3 (enhance) = 39 average.

So that puts the monk ahead by +8 damage per hit.

Power Attack has not been factored in.

To hit: 4 (Sword) +2 (WF, GWF) +7 (Str) +15 (Bab) = +28

Now, let us see. The fighter is behind in damage output by 8. So he'll need to deduct with power attack already his complete BAB advantage. However, his BAB advantage is gone thanks to divine power of the monk - the only thing remaining, therefore, are the bonuses from +2 greater weapon focus (note that the monk can spend one feat to get weapon focus as well!) and the one better enhancement bonus.
So the monk stays slightly ahead in damage.

NOW factor in that the monk has TWO more attacks from flurry, AND could use feats to have two-weapon-fighting tree (that a TH-Attacking fighter or babarian could not choose), and then the monk actually outdamages the fighter by far.

This is counterbalanced by the fact that without the divine power (7 rounds only) buff, the monk is somewhat behind in damage output (though not much, he'll retain TWO more attacks at level 15, and one more for the rest of the non-epic levels).

Do you now start to see what it means to have such a high base damage AND a higher number of attacks?

And Wis for AC, and Dex for AC. Or are your grappling monks easy to hit?

AC does not matter that much in a grapple, as you well know. Plus, for the record, the 28-point buy half orc monk could well look like this:
STR 20, DEX 12, CON 10, INT 6, WIS 14, CHR 6. Nets +3 to touch AC, more than the cleric gets (with his DEX 15).
By outside attackers, both monk and cleric lose DEX bonus to AC, but the monk retains his WIS bonus to AC.

- Giacomo