Okay for info.  I am working on celestial ward faction ae'ing lvl 6 bloodhowlers.   

3k + kills here are the parses

whirling storm v
average crit with 2 hand pericing (t5 ur blade staff of devastation dps 72) ----1723 (ranges from 1600 to 1890)
average crit with 2 t5 ur hand wraps (dps is 66 on each)   -----1202 (ranges from 1100-1300)

Either way im not seeing "double the crit" dmg.  When i use as similar as possible weapon, i get the same total crit.

1200 vs 1300.   Which makes me think that when hand to hand crits, it crits on each hand, and adds it, then when 2 handers crit, they crit for double the dmg to make it similar to the 2 hand to hand weapons.

E.G.
Main hand crits for 800, off hand goes for 400 --- you just see a 1200 crit
2 hander crits for 650 - doubles the dmg for 1300 dmg crit

Would be nice if thats how hand to hand worked.

71.38 dps - two hand blade staff  --->1070-1210 actual dmg  ==>1140 avg

2x First wraps of striking - 64.44 each   --->739-757  + 367-378 =  1106- 1135  actual dmg.  ==>1120 avg

So you might think the fist wraps are 38% better based on dps ratings, but dual wield lowers the over dps depending on the off hand.   The disparity in actual dmg is only 1.8% more on the 2 hander.

So for their actual dmg to be almost identical, and their crits to be almost identical is kinda a joke. 

Okay gonna pump some math now.
Str 520 (with no weapons) ---> 452 dmg bonus,
531 (with one) ---> 460 dmg,
544 (with two)---> 478 dmg
In Regen stance ----(no dmg modifications)
No buffs on
Weapons used: Jagged Fist wrap of striking - 64.44 dps - 141-156 weapon dmg

Trial 1:Both hands empty
Primary - 257.75  dps - 509-522Melee dmg (57-70 weapon dmg)
Off - 129 dps - 257-259 Melee dmg   (62 - 66 weapon dmg)
Total: 766-781
* Weapon dmg is estimated on the following assumptions.
1) Weapon dmg is equal to [Melee Dmg] - [Str bonus] for primary hand
2) The off hands stats are 50% of the actual stats.  AKA ( [melee dmg] *2) - [str bonus]. 

Trial 2:Jagged Main + Off hand empty
Primary ---290 (646 - 663) -->13% increase vs trial 1
Off hand --- 99.75 (198-201) --->25% decrease vs trial 1
Total Melee Dmg:   844-864 --->10% increase

Trial 3:Jagged Main + Jagged off hand
Jagged - 268.22 (596-611) 4% increase vs trial 1, 8% decrease vs trial 2
Jagged - 133.56 (296-305) 3% increase vs trial 1, 20% decrease vs trial 4
Total Melee Dmg: 892 - 916  --> 6% increase over trial 2, 17% increase over trial 1

Trial 4:Main Hand empty- Off hand Jagged
Main hand - 226 (447-458)--->13% drop vs trial 1
Jagged off hand - 164 (365-373) --->27% Increase vs trial 1,
Total melee dmg 812-831 6.4% inc vs trial 1,


Summary:
If main is identical to off hand: The off hand is 50% the dmg of the main hand. 
Main hand does the most dmg when off hand is empty
Off hand does the most dmg when main hand is empty.
You gain 6.4% dps for equiping just an off hand
You gain 10% dps for equiping just a main hand
You gain 17% for equiping both

Conclusions:
Love str.  The higher your str the more dmg added to your melee dmg and the less weapons matter.  EG.  If i buff up to 900 str (bard+cleric+disciple)  these %'s all drop to about 5% gain for equiping a weapon.   This makes sense though.   The way melee dmg is calculated is (WEapon dmg + str bonus) * Dmg modifier. 
Weapon dmg itself is rangign from 57 up to 141... A gain of ~90 dmg is extremly small when compared to the 450 dmg added from 500 str vs the 1000 dmg added from 990 str. 

If you had 0 str, Then a 64.44 dps weapon would be 64.44 primarry dps, and 32.22 off hand dps for a total of 96.66.
However when str is added, you get a combined dps of 401 (304 of it from str)

Which is why a 72 dps 2 hander goes to 460 dps (378 dps from str).  Also, note that the str dmg bonus if vs a "an average delay weapon" it actualy adds more the slower the weapon is, which is why 2 handers gain an extra 80ish dps over dual wielders!!!
* 2 hander is a t5 ur blade staff of devestation.