Is two weapon fighting unbalanced?

[aegis]

Yop, the thing not to forget in FC is that every type of fighter can end up with 3 or 4 attacks per round. There are feats for one-weapon melee attacks, one-weapon ranged attacks, unarmed attacks, and two-weapons attacks. In the end, Two Weapons Basics might seem a little less attractive than the others since it requires to have two weapons in hand (rather than one, possibly two-handed). But don't forget either that, as Desertpuma pointed out, TWB doesn't specify the type of weapon being used. In terms of versatility, this is a huge advantage.

[Desertpuma]

Imagine a fighter who carries several blackpowder pistols, has the Quickdraw feat, the Blackpowder feats and the Two Weapon feats. That is a very dangerous man I would not want to face.

[Morgenstern]

Two-weapon is in basic combat because it is neither melee, nor ranged. It's effective with both types of weapons. Two-weapon is is the most versatile of the extra attack feat chains because it covers the largest variety of mix and match options. Until multi-round ranged weapons become available, its best pairing is with Quick Draw, so the character can do things like throw 2 axes and make two sword attacks every round for the duration of a fight. The other lovely pairing is Surge of Speed so you can actually reach your opponent (or stay in range) while unleashing your full compliment of attacks.

The first feat in the chain is also generally more directly useful because getting to stand next to an opponent and beat on them with both half actions can be an iffy thing. Being able to take a move then double attack shows a much more favorable return on investment (a.k.a. comparing 1 attack at full value vs 2 attacks at -2 instead of the 2 at full vs. 3 at -2 comparison). Used defensively, you could double attack then move away, forving other oponents to play your game rather than letting them dictate the flow of battle.

The math for the multi-attack feat chains favors adding them to a character after you've already built up a few other advantages - so they are multiplying your existing non-damage roll-based advantages and because as career level goes up, attack checks tend to slightly outstrip Defense, both in base values (BAB vs. Defense) and because players tend to invest in increasing the attribute used for the majority of their attacks, while NPC Dex tends to remain static. You could easily get both feats of a multi-attack chain at level 1 for a nice 'shtick" for your character, but they really won't fully develop until about career level 6+. Something as simple as the relentless attack trick will change you performace dramatically. "I missed? Ok, how about +2 to hit on the next try?" That's excellent insurance against flat-footing yourself.

But one of the subtle and most important aspects that makes them worthwhile is critical hits. Crit hit chance per round goes up rapidly when you use the multi attack feats because threat events are NOT reduced by the -2/-5. If you are only looking at times your dice came up 19-20, you probably are only looking at hits . 'More rolls' always equals 'better' when looking for crits. With a weapon with a threat range of 19-20, the number of threats you score over time making making 4 attacks per round is essentially double the number of threats you score making 2 attacks per round, and activating crits radically shifts the landscape in a fight. That's why I mention the multi-attack feats are actually quite good against special characters too, just not for doing raw damage.

[drnuncheon]

The math for the multi-attack feat chains favors adding them to a character after you've already built up a few other advantages - so they are multiplying your existing non-damage roll-based advantages

Like, say, Flashing Weapon + Greatsword Basics?  Why yes, I would like 4 attacks at maximum damage, thanks for asking!

"I missed? Ok, how about +2 to hit on the next try?" That's excellent insurance against flat-footing yourself.

Not exactly - if any of your attacks miss you go flat-footed - so while it might help you hit more, if it triggers you're still a sitting duck at the end of your action.

[Desertpuma]

Keep in mind also that you are only flatfooted until you make your next attack or are flatfooted. This is really bad if you miss last attack and the main villain is next in the initiative order.

[Morgenstern]

The math for the multi-attack feat chains favors adding them to a character after you've already built up a few other advantages - so they are multiplying your existing non-damage roll-based advantages

Like, say, Flashing Weapon + Greatsword Basics?  Why yes, I would like 4 attacks at maximum damage, thanks for asking!

Ex-xactly

"I missed? Ok, how about +2 to hit on the next try?" That's excellent insurance against flat-footing yourself.

Not exactly - if any of your attacks miss you go flat-footed - so while it might help you hit more, if it triggers you're still a sitting duck at the end of your action.

You are correct. My bad, been a while since I wrote them.

Keep in mind also that you are only flatfooted until you make your next attack or are flatfooted. This is really bad if you miss last attack and the main villain is next in the initiative order.

Nope. The flat-footed kicks in after all of your actions. You miss, you get to sit there and take it. Hmm. Re-rolling or canceling missed attacks is gonna be gold in these builds.

[Krensky]

Keep in mind also that you are only flatfooted until you make your next attack or are flatfooted. This is really bad if you miss last attack and the main villain is next in the initiative order.

Nope. The flat-footed kicks in after all of your actions. You miss, you get to sit there and take it. Hmm. Re-rolling or canceling missed attacks is gonna be gold in these builds.

Dead-Eye with Repeating Crossbow, Quick Draw, Blackened Sky and Every Shot Counts for the win. Or the pincushion, anyway.

[Azza]

I think the two weapon fighting is great.  Just the subtle differences in FC can be so fun to discover.
Like the idea of getting multiple attacks in a round but dont want to get caught flat footed?  Get a double weapon and grab two weapon fighting and Darting Weapon.  So at the start of your initiative count you accept a -4 penalty (instead of -5 for flashing weapons and Two-weapon style) and take 2 standard actions that give two attacks each instead of a full action.
I realized this combination when I was looking at double weapons with my 3.x hat on.  The double weapon didnt look any better than the two single weapons as you can use the same size weapon in each hand.
Take that 3.x hat off and hey presto!!! 

In my group the 2nd level scout is dual wielding longswords.  That -2 penalty is huge!  You wouldn't expect him to be as effective as a soldier but I wouldn't have thought it would make such a difference.  He seems to be there mainly to soak up some of the damage!!

[Morgenstern]

I think the two weapon fighting is great.  Just the subtle differences in FC can be so fun to discover.

Heehee. I think most people miss how incredibly evil work the line (from Fencing Basics) and en garde (from Fencing Mastery) are in combination. Go into full defense and every time they miss you step back - then force them to step forward - then stab them for moving adjacent to you...

Like the idea of getting multiple attacks in a round but dont want to get caught flat footed?  Get a double weapon and grab two weapon fighting and Darting Weapon.  So at the start of your initiative count you accept a -4 penalty (instead of -5 for flashing weapons and Two-weapon style) and take 2 standard actions that give two attacks each instead of a full action.
I realized this combination when I was looking at double weapons with my 3.x hat on.  The double weapon didnt look any better than the two single weapons as you can use the same size weapon in each hand.
Take that 3.x hat off and hey presto!!!  

Yup. Double weapons occupy a very narrow niche, but they do fun things there.

In my group the 2nd level scout is dual wielding longswords.  That -2 penalty is huge!  You wouldn't expect him to be as effective as a soldier but I wouldn't have thought it would make such a difference.  He seems to be there mainly to soak up some of the damage!!

Make sure he gets a forte with edged weapons and is aware of the relentless attack trick (page 222). Every attack bonus he can scrounge up is going to help. Whirling attack (page 223) is also pretty godly for 2 weapon folks... Damage on a miss? Why thank you.

[Brakk]

I repeated my tests from yesterday and here are the results after 100 000 math loops on my PC each. It doesn't seem so bad as I originally thought. I probably won't use that damage-decreasing house rule (it would put average damage below the norm).

The main attack roll for soldier A was: 1d20 + 1 (BAB)
The main attack roll for soldier B was: 1d20 + 1 (BAB) - 2 (penalty from fighting with two weapons three times)

Soldier A with one 1d8 sword attacks AC 10 twice per round with a hit ratio of 60%. That translates to 4.8 points of average damage per round ((0.6 * 2) * 4).

Soldier A with one 1d8 sword attacks AC 13 twice per round with a hit ratio of 45%. That translates to 3.6 points of average damage per round ((0.45 * 2) * 4).

Soldier B with two 1d8 swords attacks AC 10 three times per round with a hit ratio of 50%. That translates to 6 points of average damage per round ((0.5 * 3) * 4).

Soldier B with two 1d8 swords attacks AC 13 three times per round with a hit ratio of 35%. That translates to 4.2 points of average damage per round ((0.35 * 3) * 4).

Here's the sum for both of them.

Soldier A: 4.8 + 3.6 = 8.4
Soldier B: 6 + 4.2 = 10.2

So it seems that some sort of advantage (18%) for soldier B does exist on an average level. This could be translated that every 5th round soldier B gets an additional bonus round.

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And I tested a -5 penalty for 4 attacks as well.

The main attack roll for soldier B was: 1d20 + 1 (BAB) - 5 (penalty from fighting with two weapons four times)

Soldier B with two 1d8 swords attacks AC 10 four times per round with a hit ratio of 35%. That translates to 5.6 points of average damage per round ((0.35 * 4) * 4).

Soldier B with two 1d8 swords attacks AC 13 four times per round with a hit ratio of 20%. That translates to 3.2 points of average damage per round ((0.2 * 4) * 4).

The sum of it.
Soldier B: 5.6 + 3.2 = 8.8

Still better than soldier A's but worse than attacking only three times.

[tenebrae]

And those -2 and -5 penalties start to count a lot more as the target's Defense climbs higher...

[Daedalus]

I still prefer Flashing weapon with a two-handed weapon in terms of potential damage output anyway, since it could be massive in he hands of a Giant with a scaled-up claymore and good reach.  Two-Weapon Style isn't going to let a character blast characters 3 or 4 squares away for 2d8+Strengh each hit, unless we're talking about a Martial Artist...even then Greatswords properly upgraded can offer up to +3 Guard which is no joke either and is not a half-bad substitution for shield fighting.