Mike Mearls: so here’s the first part of my two-weapon fighting house rule

[guachi]

Your math is off. You don't double stat bonus on a crit, only damage dice. Also, your average damage from GWF is off.

It's GWF = .65*11.333 + .05*8.333 = 7.78
TWF = .65*6.5 + .05*3.5 = 4.075*2 = 8.15

That's for a 65% hit chance, level 1, and the appropriate fighting style.

 

[Tomice]

I'm no expert in any way, but is anything wrong with this simple house rule?

FEAT: Dual Wielder
You master fighting with two weapons, gaining the following benefits:
You gain a +1 bonus to AC while you are wielding a separate melee weapon in each hand.
When you engage in two-weapon fighting, you can add your ability modifier to the damage of the second attack.
You can draw or stow two one-handed weapons when you would normally be able to draw or stow only one.

FEAT: Heavy Dual Wielder
You can use two-weapon fighting even when the one-handed melee weapons you are wielding aren’t light.
Requires Dual Wielder Feat and at least 13 Strength.

FEAT: Fluent Dual Wielder
You can make one additional attack with your off-hand as part of the Attack Action. If you do, you can't use your bonus action for another attack this turn.
Requires Dual Wielder Feat and at least 13 Dexterity.

FIGHTING STYLE: Two-Weapon Fighting
Choose any of these feats: Dual Wielder, Heavy Dual Wielder, Fluent Dual Wielder.
Prerequisites still apply.
________________________________________________________

Seems way more logical for me than the official rule and much easier than Mike Mearls house rule.
It also makes TWF less of a trap choice on higher levels and for classes other than Rogue (I know it's a buff, but a needed one IMHO).
The fact that dual Rapiers are less accessible this way is intended to leave the Rapier as something unique for Rogues (and other finesse weapon users) without Dual Wielding.

If this is too strong, one could remove the +1AC.

 

[Eubani]

Feat chains have gone the way of the Dodo thankfully.

 

[Quartz]

Note: A dueling style doesn't really have a feat that give more damage except for Savage Attacker, which takes the average on a d8 to 6.25.

In theory Shield Master is the feat for the duellist - bash the opponent to shove it so your mates get Reaction attacks. Plus the save for no damage is nice.

 

[WaterRabbit]

In theory Shield Master is the feat for the duellist - bash the opponent to shove it so your mates get Reaction attacks. Plus the save for no damage is nice.

I agree, but it is hard to calculate the aDRP for a shove, so I looked at Savage Attacker which looks better than I expected. Also, your mates don't get reactions attacks against creatures that were involuntarily moved. What I have seen more commonly is to knock the creature prone so that your mates get advantage on the attack.

 

[WaterRabbit]

It also makes TWF less of a trap choice on higher levels and for classes other than Rogue (I know it's a buff, but a needed one IMHO).
The fact that dual Rapiers are less accessible this way is intended to leave the Rapier as something unique for Rogues (and other finesse weapon users) without Dual Wielding.

I have seen this said, but still don't understand why it is a "trap" choice.

A fighter with the Dual Wielder feat gets 4 attacks per round. Only a Fighter with a longbow or heavy crossbow does more damage per round (the crossbow requires the extra feat). The only trap aspect here is that it uses the bonus action to get the 4th attack. However, if that wasn't the case then there would be no reason at all not to take Dual Wielder and Two-Weapon Fighting.

So perhaps you can explain why you think this is a trap feat? One of the main advantages of TWF is that it allows the use of two different types of damage (B,P,S) or enchantments.

 

[Quartz]

What I have seen more commonly is to knock the creature prone so that your mates get advantage on the attack.

Yes. Before it got errataed the thing to do was to use the shove then get advantage on your own attacks.

 

[Hawk Diesel]

So seeing this conversation has got me to thinking about Two-Weapon Fighting. I know it is a common house rule to allow for the extra attack as part of the attack action, and I've vacillated back and forth about that. But as I said, this thread got me thinking. What if we changed TWF into the following:

Two-Weapon Fighting
When you take the Attack action and attack with a light melee weapon that you’re holding in one hand, you can use a reaction to make an additional attack with your off-hand. This additional attack must be with a different light melee weapon that you’re holding, an unarmed strike, or a natural weapon. You don’t add your ability modifier to the damage of the bonus attack, unless that modifier is negative.

If either weapon has the thrown property, you can throw the weapon, instead of making a melee attack with it.

Ways this changes current Two-Weapon Fighting

-Allows more wide use of the reaction. In my gaming experience, reactions are seldom used except by Polearm Masters, Sentinels, or specific kinds of magic users. This widens their use.

-Opens the door to unarmed strikes or natural attacks with TWF. Seems silly that 5e makes a distinction between these attack modalities, but apparently it does. This also means it is a tactic monsters can easily use against the party, even if they don't have melee weapons per se.

-Reduces the competition for bonus action abilities such as Cunning Action, Hex/Hunter’s Mark, Flurry of Blows, ect

-Opens the door for a different kind of Duelist. Now, if you choose not to wield a shield, you can make an unarmed strike and add your duelist damage to it. Or a Champion fighter that takes duelist and TWF, and can add the STR mod and damage bonus to his unarmed strike (especially useful if feats are not in use). I think that is kind of interesting.

-Increases the number of attacks a monk can make. A low-level monk can now make 3 attacks with their martial arts ability, or four with Flurry of Blows. This increases to 5 attacks by level 5. Not sure if this is good or bad.

 

[Yunru]

Only a Fighter with a longbow or heavy crossbow does more damage per round (the crossbow requires the extra feat).

Again, your maths is wrong.
From 4 attacks I assume we're level 11. You mention Dual Wielder so I'll assume one feat.

A Dual Wielder uses two Longswords at 1d8+5 each.
From the 4 attacks, we have an average damage of 38 (which will have to be multiplied by accuracy).
From the chance of critting, we have an average damage of 4*0.05*4.5, which is 0.9.

A Great Weapon Master uses a Greatsword at 2d6+5.
From the 3 attacks (not using the -5/+10, because otherwise this table becomes 5 columns wider) we have an average damage of 40 (again, multiplied by accuracy).
5% of the time, we crit, adding not just 2d6, but another attack, making things complicated.
First the damage bonus from the crit: 0.05*25 = 1.25
Second the damage from the bonus attack: 0.05*13.33333 = 0.66666666 (again, multiplied by accuracy)
Thirdly the damage bonus from the crit from the bonus attack: 0.05*0.05*8.3333333= 0.020833333

A Crossbow Expert Archer uses a Hand Crossbow at 1d6+5. It also has 4 attacks.
From the attacks: 34 damage (multiplied by accuracy)
From the crits: 4*3.5*0.05 = 0.7

A Duelist, with no feats, deals 1d8+7 three times.
From the attacks: 34.5 damage (* accuracy)
From the crits: 3*0.05*4.5 = 0.675

So let's put this into a table, red means TWF is worse, green is better:

Style \ AC	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Two Weapon Fighting (Dual Wielder)	37	37	35.1	33.2	31.3	29.4	27.5	25.6	23.7	21.8	19.9	18.0	16.1	14.2	12.3	10.4	8.5	6.6	4.7	2.8	2.8	2.8
Duelist (No Feat)	33.45	33.45	31.725	30	28.275	26.55	24.825	23.1	21.375	19.65	17.925	16.2	14.475	12.75	11.025	9.3	7.575	5.85	4.125	2.4	2.4	2.4
Archery (Crossbow Expert)	33	33	33	33	31.3	29.6	27.9	26.2	24.5	22.8	21.1	19.4	17.7	16	14.3	12.6	10.9	9.2	7.5	5.8	4.1	2.4
Great Weapon Fighter (Great Weapon Master)	26.1791333(...)	26.1791333(...)	24.9083	23.6374666(...)	22.3666333(...)	21.0958	19.8249666(...)	18.5541333(...)	17.2833	16.0124666(...)	14.7416333(...)	13.4708	12.1999666(...)	10.9291333(...)	9.6583	8.3874666(...)	7.1166333(...)	5.8458	4.5749666(...)	3.3041333(...)	3.3041333(...)	3.3041333(...)

N.B. That the above doesn't include Action Surge, which favours every style bar TWF.
I'd do one for GWF with -5/+10, and one for every style with Action Surge, but I'm tired of all the maths.

 

[WaterRabbit]

Again, your maths is wrong.

Instead of accusing someone of bad math, maybe you should check your own work. But even with your mistakes, we come to the same conclusion, TWF is generally better. So if it is generally better why are people calling it a trap and why does it need to be modified?

----------------
My Assumptions:
1st Level Fighter: STR/DEX: 15 (Point Buy) +1 (Variant Human) = 16 (+3 dmg) Dual Wielder (1d8 damage Longsword/Rapier)
4th Level ASI STR/DEX goes to 18 (+4 dmg)
5th Level Extra Attack (2)
6th Level ASI STR/DEX goes to 20 (+5 dmg)
8th Level ASI takes a feat (Would be Crossbow Expert or Sharpshooter for the archery comparison)
11th Level Extra Attack (3)

The damage for 11th level fighter would be: (1d8 +5) * 4 attacks = 9.5 * 4 = 38 points of damage without taking misses or crits into account (we agree here).
At a 65% chance to hit (your 17 column): (1d8+5) * 0.6 + (1d8+5) * 2 * .05 = 9.5 * 0.6 + 19 * 0.05 = 5.7 + 0.95 = 6.65 * 4 attacks = 26.6 aDPR. (here you are off by 1).

You don't seem to be taking into account the average damage of GWF [2d6 = average 7 without GWF, but 7.42 with GWF] (if anything GWF probably should be just getting a flat bonus to damage)

My analysis was done taking into account GWM, which should only add a row to your table not 5 columns.
(Also you should round to 2 decimals as the ones beyond are insignificant; I was about to rebuilt my table so I could find the sweet spot where Power Attack is worse than not taking it, I can also add action surge).

I agree action surge doesn't give 8 attacks (only 7), but as everyone else is only getting 6 attacks, it doesn't really help or hurt TWF. But this also affects the hand crossbow user which might make the heavy x-bow a better choice.

TL;DR: TWF still seems to do more damage / round than Duelist or Great Weapon Fighter. It is worse than Archery at high to hit numbers. So why does it need to be messed with?