I warn you, this is a serious topic on how Dual-Wielding can be implemented in the [hopefully] upcoming expansion.
In the expansions, ANet has hinted in the release of new... things. They described it like Magic: the Gathering - the new stuff won't be required to play, but will allow a lot more diversity in gameplay. So I came up with this - for each class, among other things, release a new primary attribute. It'd be like introducing a new thing in magic, like cycling or kickers. An example for Mesmers would be Persistancy, an attribute that passively increases the duration of hexes. Another is Concentration for Elementalists, which would create a small percentage of ignoring interruption per point. See where I'm headed?
I propose Dual Wielding as the new primary attribute for Warriors [from now on, Dual-Wielding will be abbreviated as DWing]. This would be very difficult not to implement, but to balance. Adrenaline would be achieved at a much higher rate, and two weapons would outdamage a hammer anyday. So how would we do this? I have come up with two ways, both of which deal with what benefit points in this attribute would provide.
I withdrew the New Primary attribute suggestion a little later. See below for details.
1] Make it so you cannot DW until you have at least one point in this attribute. Then, setting the default miss chance of your off-hand at 95%, have each point reduce this miss chance by 5%.
2] Make specific off-hand weapons. Each one should do around 40% damage compared to a standard one-handed weapon and come with an attribute point requirement, like many weapons past Pretty Ascalon. To balance the adrenaline issue, set the adrenaline generation to a default 0%, then have each point in this attribute generate 5% of the adrenaline a normal hit would.
Both of the above suggestions cover the damage and adrenaline problem. It justifies the extra damage and adrenaline by the fact that you are forgoing whatever your off-hand is carrying. However, there are quite a few uncovered issues, some of which are
-the poor hammer. Hammers could possibly become obselete, as DWing would provide both a higher DPS and adrenaline recharge. This problem could be solved simply by having Hammer Master increase both damage range and swing speed.
-the stacking of attributes. Imagine the horrors of Axe Mastery applying to both axes. A solution is to create a weapon class specifically for Off-Hand weapons or just have damage range increases from other attributes apply only to the primary hand.
-other attack skills. Although this isn't too large a problem, having Galrath Strike occuring with your off-hand weapon might be a problem. Having non-DW attack skills apply only to the primary hand should solve this.
-being able to use both Axe and Sword skills. Imagine the possibilities... anyway, this could be prevented by making off-hand weapons a class of their own.
-tough choices. The percentages above have to adjusted to the point that choosing to DW is not automatic, but requires weighing the benefits of other off-hand items. Another way you could balance this is make current off-hand items on par with DWing.
Skills for this attribute would be a joy to make, for those who actually know how to spar with weapons to your average comic/manga fan.
For 1], a skill could be Twin Blades, an adrenaline-based skill that allows you to swing simultaneously with both weapons on your next attack, give the off-hand weapon the normal miss chance, and do x extra damage [to balance for those who have poured points into the attribute].
For 2], a skill could be Follow-Through, an attack skill for your off-hand, where, if both your last primary attack and this attack hit, provides 1-4 adrenaline.
However, stances can also rise from this. One could be Duelist's Stance, an elite stance that provides a 75% dodge chance for x seconds at the cost of your off-hand attack. Another could be Jester's Dance, a stance in which all of your primary attacks will miss, but your off-hand does double damage for x seconds.
In conclusion, I believe that Dual-Wielding could be a very interesting addition to a future expansion of Guild Wars. It would provides a whole new dimension to combat as well a new motivation to be a Warrior primary.
Any constructive criticism is welcomed.
04.19.05 - The last several people who posted didn't read the entire thread before posting and based all their stuff on just this post [will I will admitted is pretty flawed]. To remediate this, I have Copy/Pasted my revised suggestion here to save time.
I take back my initial suggestion and now believe that dual-wielding should not be a primary attribute. I have thought about it and come up with two revised suggestions.
3] This follows the path of fantasy dual-wielding, with weapons of identical size or type.
You may equip any two one-handed weapons of the same type [ie axe, sword, or anything released in future expansions]. Both suffer from an initial 54% decreased attack speed, which is reduced by 4% for each point in the attribute. The amount of adrenaline you gain per hit is reduced by the same amount your attack speed is.
This would mean that, with one point in DW, your attack speed would remain the same [without any, DWing would actually be a disadvantage]. As you put points, you would gain increased DPS and adrenaline gain as compared to just one weapon.
Skills for this build would pick up on the two weapons. Examples include [some revised]:
-Dervish: Elite, Stance; 10e, 2cast, 30cd; For 5-15sec, your attacks gain 50% more adrenaline. You must be wielding two weapons to cast this skill.
-Dual Swing: Attack Skill; 8adrenaline; Attack with both weapons. Both do 1-10 more damage.
-Whirlwind Attack [D&D, anyone?]: Attack Skill; 5e, 12cd; Lose all adrenaline. Your next two attacks will hit all adjacent targets. Each attack suffers a 33% miss chance.
This would require the implementation of an adrenaline system that keeps tracks of fractions/decimals/percentages, but that isn't too difficult. Other than that, I think I covered everything.
4] This follows the path of real combat with the use of off-hand weapons. The attribute would probably not be named DW, but something along the lines of Off-Hand Skill [I know, that was lame]. A new class of weapons called Off-Hand Weapons would be created. This would consist of daggers, gauches, hatchets, and other small weapons. Anyone could arm an off-hand weapon instead of a focus or shield. Hits with the off-hand would not generate adrenaline.
Each point in Off-Hand Skill would would minutely increase maximum damage and passively add a small percentage [maybe 1%-3%] to get a critical hit with the off-hand weapon.
Skills would revolve around the elusive nature of the off-hand weapon. Examples include [some revised]:
-Duelist's Stance: Stance; 10e, 1cast, 45cd; For 3-15sec, you would gain 50% dodge but cannot make attacks with your off-hand.
-Follow Through: Elite, Attack Skill, applies to your next off-hand attack; 5e, 12cd; If this attack hits, gain 1-5 adrenaline.
-Deceitful Blade: Attack Skill; 9ad;Your next primary-hand attack misses. The following off-hand attack automatically crits and deals an extra 1-10 damage on top of that.
This would require almost no change to the current system other than the introduction of the off-hand weapons themselves.
Please post with criticism.
06.23.05 - I could see how a Rogue/Assassin class could work with two types of DWing - the traditional dagger/rapier [ie Artemis Entreri] or two daggers [ie the poor bloke who tries fighting Drizzt in Waterdeep]. [you wanted Drizzt fanboyism, Talesin?]
Both of the systems I am proposing can be traced back to 3], as I believe that introducing weapons that allow a faster attack speed than swords/axes will imbalance the game when it comes to skills like Mark of Pain, Illusionary Weaponry, etc. I may post another system later that ignores this personal qualm, but I'll do these first.
5] This is a suggestion for DWing for a new profession using both a primary and off-hand weapons.
Create two new weapons, both with a swingrate of of three seconds. That way, with two such weapons, the swingrate ends up 1.5 seconds, which is faster than a hammer but slower than a sword/axe.
One new weapon would be the rapier. Alternative names for items in the game could be foil, epee, saber, etc. With it's slower attack speed, I suggest it's damage be 17-29. This would provide for a good balance between sword/axe and hammer damage [since this is not the warrior class, it's damage will be less], but will allow for sizable crits. In all other respects, it should be treated like any normal melee weapon, with similar upgrades.
The other new weapon would be off-hand daggers. Alternative names for items in the game could be parrying dagger, main gauche, sword-breaker, etc. Given the same attack speed, it would do significantly less damage than the other, doing only 11-17 damage. However, this handy little item would provide an energy and shield armor bonus of up to +7 each.* To be perfectly honest, I don't know how upgrades could be made for this weapon; it could be the same as the current weapons or completely new unique to its support status.
The main attribute for these weapons could be called Swashbuckling, and would cover requirements and crits for both weapons. You would not get the full energy and shield AL bonus, along with weapon damage, if you did not meet the attribute req.
6] This is a suggestion for DWing on a new profession using two weapons of equal size.
Create a new weapon. Each would have a swingrate of 2.5 seconds. That way, with two such weapons, the swingrate ends up 1.25 seconds, which is slightly faster than a sword/axe [1.33 seconds].
To be honest, I can't imagine an assassin/rogue using two full-sized weapons, so I believe the new weapon would be a dagger. Alternative names for items in the game could be sword-breaker, kris blade, dagger [

I'm not quite sure what you could name the attribute, but it would cover both requirements and crits. You would not get the full energy bonus or shield AL bonuses, along with weapon damage, unless you meet the attribute req.
An issue that must be addressed with both suggestions is their use with current weapons. Using either with a sword/axe would create a very fast swingrate, as the latter would strike about twice in the span of one of the off-hand's attacks. Aside from graphics issues of two weapons swinging at different rates, this could be remedied by simply doubling the swing speed of the said sword/axe when one of the new off-hand weapons I suggested.
I'd also like to set out my definition of constructive criticism, as the mere concept seems to be lost on a couple recent posters.
I consider constructive criticism to be suggestions, commentary, and notice of flaws regarding my suggestions that could help me come up with a better system. This does not include "0^^g |=@/|/|30\/111" or "I'm sorry, but your suggestion sucks" unless it includes reasons as to why.
Although general suggestions and comments still fine, some specifics I would like to hear are the names for the weapons mentioned and a name for the attributes. I'd also be very glad if someone could calculate the swingrate of using a sword [1.33s] and each of the suggestions [3s for 5] and 2.5s for 6]].
I'll comment on what everyone else has posted later, as I am guilty of not yet reading the older posts [it's very old, probably the oldest active one in Sardelac].
*Historically speaking, the choice of whether to use the main or off-hand weapon for defense was a personal preference, but often times the other way around. The term "parrying dagger" is a tribute to its deceptive nature, as it was normally the longer blade used to parry and maneuver the opponent's and the dagger that delivered the fatal blow.
06.25.05
7] Make two new off-hand weapons. Both are linked to a new attribute called Ambidexterity, and the higher end ones will require it. Both of these weapons suffer a 75% miss chance, which is decreased by 3% per point in the attribute.
One of these new weapons will require Strength as well. These weapons do about 50%-75% damage as compared to a normal one-handed weapon [these numbers are subject to balance].
The other weapon would require Tactics. These weapons would provide a block rate of 4%-20%. To balance this, points in Tactics now inherently reduce block/miss rates by x% per point.
I don't know how I would balance the adrenaline issue with this one.
~inspired by Sgt Allen
8] Create a new class of off-hand items linked to Strength. This item simply provides a damage bonus to the primary hand of %5-20%.
To satisfy the die-hard DWing fans, there will probably be a changed animation for those who are using this item. That, and/or they can have two number pop up when you attack - the normal damage of the primary weapon and the damage the off-hand weapon added.
This would solve the adrenaline problem by simply not generating it. Hammers will probably need a small speed-buff.
~inspired by MasterDinadan