Some real world numbers on DMC: Hurricane.

On Throne of the 4 Winds last night we did around 10 attempts until the kill (ranged tank kept getting blown off).

DMC Hurricane did between 1.1 - 3.3% of my damage per fight. Average seemed to be about 1.7% normally.

I think the 3.3% high was when I was swiping the adds on the left boss. It procced alot with Swipe.

Source

So we will be switchting to "Agile shadowspirit Diamond" I assume.
Now I am wondering if not gemming for straight agility will still benifit us?

In case you were not aware, right now 352 4PvP beats 2x359+2x346 non-tier with a comfortable margin. So I would recommend obtaining Bloodthirsty 4set with reputation gloves as offset [Liar's Handwraps]

Here is a comparison of 4.0.3 sets, to spur your imagination. They were compiled with the assumption that we use Red+Green pairing to obtain PvE damage stats - This will change in 4.0.6.

PvE Set (Best in Slot t11.0)
4Piece, [Tsanga's Helm] offset due to tier chest socket bonus when using [Relentless Earthsiege Diamond]
Stats, assuming 100% uptime on Tia's Grace + Fluid Death

	W-DPS	723
	AGI	4870
	STR	167
	Mastery	2257
	Crit	1473
	Haste	890
	Hit	550
	Exp	113
	AP	947

Buffs: Full minus DI, UF, ToTT, Shattering Throw
PvE RSV with no set bonus

	Stat	Calc	Sim
	MeleeDps	4.12431	3.98189
	Agility	2.95117	2.93474
	Strength	2.23037	2.20835
	MasteryRating	1.18198	1.17588
	Ap	1.06208	1.0538
	CritRating	1.00125	0.98716
	HasteRating	0.91972	0.9071
	HitRating	0.84041	0.80257
	ExpertiseRating	0.84041	0.80577

PvP Set
4Piece, [Tsanga's Helm] Offset due to resilience socket bonus on PvP Helm, as well as 30Agi being the best available socket bonus.
===
(including 250 Agi PvP bonus)

	W-DPS	723
	AGI	5160
	STR	167
	Mastery	2134
	Crit	1353
	Haste	552
	Hit	390
	Exp	96
	AP	947

Buffs: Full minus DI, UF, ToTT, Shattering Throw

	Stat	Calc	Sim
	MeleeDps	4.00754	3.84343
	Agility	2.89165	2.85773
	Strength	2.17515	2.15917
	MasteryRating	1.22282	1.21445
	Ap	1.03579	1.02921
	CritRating	0.99874	0.99227
	HasteRating	0.938	0.85209
	HitRating	0.85091	0.7544
	ExpertiseRating	0.85091	0.75364

Note that from Mew Simulations, PvP set is worse by approx. 685dps (and it is easier to obtain with 5games a week).
Notes for now (4.0.3)
Since the PvE set is itself worth AT LEAST 811.87033 DPS, then you should havea a backup plan to obtain 4piece PvP, as this will net you a greater damage output than offpieces. This is particularly true if you are in a guild that will not be killing Cho'gall / Nefarion for a while, since these are required to complete your 4piece. You may be able to get a better benefit from 2t11, depending on what drops for you. Vicious 4set is perfectly viable, and desirable for PvE dps.
I myself have TWO feral druids, one who raids at hard mode level and the other who has 4piece PvP, and unbuffed they do such similar damage it frustrates me (within 300dps, despite clear gear differences).
Notes for later (4.0.6)
Let's assume Blizzard is perfect at balancing, and they choose to balance us at the Tier11.0 level. Here is some napkin thought. Bleeds are about 50% of our damage (Rip+Rake) and both spells are being cut by 10% damage. This will result in a 50%*10% = 5% dps loss. Shred is about 20% of our damage. This is being buffed by about 25%. This will result in a 20%*25% = 5% dps gain. So overall our dps should be similar.

However, our RSV will change. From simple assumptions, Mastery will decrease in value by 10%. Using the PvE RSV this is a drop from 1.176 to 1.058. Since Mastery is still greater than our other secondary stats we won't be reforging/regemming differently in this regard. (Yay)

But since we lost dps from Mastery, where do we regain this dps? Shred damage increases in value so this affects everything EXCEPT mastery. Omen of clarity has a higher value thus HIT has a higher value because you do not want to miss the proc as much anymore. Haste gives you more regen+OoC for shred. I imagine agility would also be increased for the decrease to the value of mastery and since we have a lot more agility and less mastery in the PvP set, then the cat damage readjustment could see 4piece PvP dps approach 4t11 PvE dps.

Using the RSV from the post above, You need ~2.5 Mastery for every 1 agility you lose, prior to the bleed rebalance.
After the rebalance you will need ~2.77 Mastery for every 1 agility you lose. Since Mastery is the best secondary stat, this means for every non-red gem you need to gain at least 50-55.4 of a secondary stat, if not more. The highest secondary stat socket bonus in this tier is +30haste. Even if this was mastery it would not be enough.

Thus we should only consider agility socket bonuses.

Hence we will be gemming pure red, except if there is a ~12agi bonus for yellow and ~17agi bonus for blue. ([Tsanga's Helm], [Stormrider's Headpiece], [Stormrider's Raiment])

As for whether we will be switching metagems: It depends how much agility and what the %modifier on critical strike damage is. This is likely to be a direct upgrade over relentless, however they could be tricky and do +50agility +2%critical strike damage. [Relentless Earthsiege Diamond] will have its requirement changed to 3 Red Gems as well, so it is certain that this will be one of the best 2 gems.

Neither players nor mobs/bosses can dodge or parry while they are casting a spell, so capping expertise won't help.

The relatively high cost of our interrupt makes us an unlikely candidate for interrupt duty. However, it's nice to have the option if your raid comp is light on interrupters. I'm not called to interrupt due to the combination of high cost and signifigant impact on my DPS rotation, but I like being able to backup someone in a pinch.

If there's any chance you'll be depended on for interrupts, make sure you've picked up [Bloodthirsty Gladiator's Dragonhide Gloves]. It will be a DPS loss over PvE gloves but it makes interrupting much easier and raid wipes are even worse DPS.

Editing the item in Rawr, even with 100% proc chance puts it in between [Key to the Endless Chamber] and [Right Eye of Rajh] for my character (so about 10ish pre-raid items still better than it). Napkin math using mew RSVs agrees.

The excuse I'm used to hearing on this part is "I don't care about your DPS, just interrupt even if you have chance to miss" since we put about 2-3 interrupts / cycle just incase someone misses/chokes. I find my self either pooling energy too much or having to use TF to interupt instead of dps

I have thought this true for a while but was unable to get RAWR to recognize the 4pc pvp bonus. That and for some reason most Pre-raid BIS lists seem to undervalue the pvp items or fail to include them at all (probably not taking into account the bonus).

Assuming the pvp set is best, has anyone determined which 4 pieces are best suited to get the bonus and should we only break the bonus for 2p T11 or better? I'm considering the chest,legs,shoulders, and gloves + [Tsanga's Helm].

Concerning Glyph of Shred, I did some testing in the Argent Tournament melee target and it appears that the glyph is not refreshing Rip's duration when the Rip has been refreshed by a FB under 25% target's health. With regards to the glyph, the Rip is treated not as being a new one reapplied, but as an existing one merely refreshed and the counter of glyph refreshes seems to remain unchanged. That, of course, may be intended behaviour, but it reduces the time one has to rebuild CP's for SR refresh and another FB under 25% target's health. It may also change the value of the glyph, as it is not doing anything for roughly 25% of the time.