Is this change to the Two-Weapon Fighting fighting style balanced?

Question

Here is my modified version of the Two-Weapon Fighting fighting style.

Two-Weapon Fighting

• Once per attack, when you engage in two-weapon fighting and before rolling, you can take a -5 to hit for that attack. Until the end of this turn, you can apply a +5 to a two-weapon attack against that same target before rolling. If you have multiple +5's against the same target, you can apply however many you want to an attack.
• Add 2 damage to your off-hand attacks.
• You can draw or stow an additional weapon, provided it is one-handed.

Note, all page numbers come from the Player's Handbook unless stayed otherwise and I'm ignoring any Feats or other house rules that could affect this.

I've been playing D&D for a few different characters and noticed that with the melee types (even with those who've invested in it), fighting with two weapons seems to be discouraged by the mechanics past lvl 4. From the various goodies that you have to abstain from(class features, spells, etc), having stagnancy issues, and awkward action economy interactions; Two-Weapon Fighting, as a mechanic, is littered with issues beyond level 3 and these only become more pronounced as you gain levels and multi-class. Specifically, the problems that plague Two-Weapon fighting as a tactic comes from the base mechanics (the style meant for it is a band aid that fails to address any of the fundamental issues this route has) and can be boiled down to the following: the Free interaction, Style stagnation, and opportunity costs.

The Free Interaction

This issue concerns itself with the base mechanics since the style buffs the extra attack the mechanic gives. Here, a character who has made an investment in fighting with 2 weapons by taking the Two-Weapon Fighting Style has to have (by RAW at least) a feat (pg 165, Dual Wielder) or always have one weapon drawn in order to attack with both on their first turn of combat. Otherwise, they have to attack with one weapon, use their action to draw their 2nd weapon (pg 130), do a utility action (pg 192, Actions in Combat) or wait until their next turn to use the free interaction(pg 190, Other Activities On Your Turn). Admittedly, this is pretty easy to get around and can be a moot point, but deserves pointing out because it sucks when the limelight happens to find it and it just feels weird when you think about it.

Style Stagnation

What this refers to is that the Two-Weapon Fighting Style will only ever affect one thing, the damage of a single attack (regardless of what they do) because that is all the base mechanics of Two-weapon fighting allows. Only one other style has to deal with a similar type of restriction, Protection. This ends up hurting the Two-weapon folks as they level. The resulting progression of their number of attacks, when compared to other's attack count, is that at lv 1-3 they get 100% of the attacks of everyone else, lv 4-10 it becomes 50% to most other melee characters. For fighters, at lv 11 this become a 33% difference and lv 20 the 'advantage' of the mechanic and thus getting a benefit from this style is a buff to a measly 20% over what your competition can do. That's actually kinda depressing now that I worked that out :/. All of which makes the Two-weapon Style feel even more insignificant when you look at how other styles mesh with their abilities and associated mechanics while your abilities and the Two-Weapon mechanics don't.

Opportunity Cost

The opportunity cost issue stems from the fact that in order to benefit from the Two-Weapon Fighting Style, you have to use your bonus action to get a off-hand attack going. When you look at the other Styles, only Protection is involved with something other than an attack action in the action economy, it using your reaction. The rest require nothing but remembering to apply their affect to one of the most used rolls in the game and those typically passively scale up by affecting an increased number of rolls. This makes getting any benefit from the Two-Weapon style in direct contest with certain spells (ex Hex), class features (ex a battle master's maneuvers, Eldritch Knight's war magic,etc), and any other action that would invalidate you being able to do an off-hand attack (and this isn't even an exhaustive list). As you get higher level this becomes increasingly worse, making your investment becomes more and more costly to try capitalizing on.

This all adds up to a rather disappointing experience for anyone who wants to swing two weapons around better than anyone else and really makes me wonder what made Wizards think that having so many hoops and costs just to buff a single (1) extra attack gotten from a niche mechanic with minor damage and nothing more, was a good idea. But I digress.

The Question

With all that in mind, the question(s). Does the alteration above to the Two-Weapon Fighting Style address the outlined problems without making it too strong in comparison to other Fighting Styles? Is it too rigid (i.e. only one way to be a dual wielder) in comparison to other tactics (ex Two-Handed, ranged, sword and board)? Is there an obvious edge case that breaks this sideways?

If you could show the math involved with answering any of these or leaving a link to a spot that does would be very appreciated. Thoughtful answers for issues that this has are welcome though!

Answer 1

The first bullet point of your modified Two Weapon fighting style seems to rely upon another, unstated house rule: That you must declare all your attack targets up front and make all the attack rolls at the same time, before you learn which ones hit and how much damage they deal.

That's not a normal part of the rules, though it might be a common shortcut to streamline things at your table. The rules as written let you roll one attack, find out if it hit, then roll its damage and learn the results of that damage, all before you go on to make any further attacks you're capable of. You can even move in between attacks, which is very useful when you killed your first target with one attack and need to move to engage another one.

So your modified fighting style isn't unbalanced, per se, but rather sort of nonsensical when otherwise playing with the rules as written, since you don't normally make multiple attack rolls at the same time. You might be able to rephrase it to better explain how it's modifying the normal rules, and then a balance consideration might be possible:

• If you use your bonus action for two weapon fighting, you may make the attack roll for your second weapon at the same time you roll an attack against the same target with your primary weapon. If you do so, you may apply a positive modifier of up to +5 to any one of the attack rolls, and a negative modifier of the same magnitude to the other attack roll. You must choose the modifier to use before you know whether either of the dice resulted in a hit or a miss.

I suspect this is too strong, though I'm not a balance expert. It gives you two main advantages:

First, if you roll one mediocre roll and one very bad one, you can dump the bad one by -5 (which doesn't really cost you anything since it was going to miss anyway) and get a +5 to the better one. That means you'll almost never completely whiff when attacking twice. This is substantially better than getting advantage on one attack, since you also get +5 on the better of the two rolls!

Second, it helps when you have one very good roll, and one mediocre one. You can take a penalty on the good roll to turn the bad one into something a bit better. This can mean you go from one hit and one miss to two hits. If you have deduced the enemy's exact AC (which is pretty easy to do after they've been attacked a few times, and many DMs will just tell it to you, especially when the AC is from something obvious, like chainmail), you will know exactly how large of a modifier you can safely apply. So I suspect the potential downside of missing with both attacks when penalizing your better roll will be almost nonexistent in practice. The house rule should probably forbid putting a -5 modifier on a critical hit (since a natural 20 always hits, regardless of modifiers or AC).

A few changes might make it a bit more balanced. You could require the player using the ability to decide how to apply the modifiers before rolling (e.g. "I'll take a -2 on my dagger for a +2 on my shortsword"). Or you could limit how the modifiers can be applied. Maybe the negative modifier can only be put on the off-hand attack roll? Or only on the higher of the two rolls, to prevent the dumping of a -5 on an obvious miss?

Answer 2

Your big stated concerns in the question are that two-weapon fighting requires a feat to properly draw your weapons, and that it ties up your bonus action in combat.

You should solve that problem instead of making up new mechanics, for example this style

• You can add your ability modifier to the damage of the offhand attack when using Two-Weapon Fighting
• You can draw two weapons at once during the same interaction
• The offhand attack of Two-Weapon Fighting can be taken as an additional attack during your Attack action instead of as a bonus action.

I'm not certain this is balanced (it's probably a little overpowered), but it's a more directed attempt at accomplishing your stated goals.

Answer 3

The rule design is not completely thought though

• What about a nat 20? This is considered an automatic hit. Does transfering any number of points potentially result in a miss?
• You may not know all the attacks you're taking beforehand. If you kill an enemy with one of your attacks you may want to shove the next one. If you allow the player to decide later to shove even if you keep the (modified) roll, the decision could still be a tactical one, since shoving results in a contested roll and even a bad roll may have a chance of succeeding.
• You may not know at the start of the turn, which rolls have (dis)advantage or and which do not. E.g. a PC is surrounded by 2 enemies one of which is flanked providing him with advantage and one which is invisible providing him with disadvantage. He's got Extra Attack (2). He decides to get rid of the flanked enemy first. You cannot tell at the start of the round, if the flanked enemy goes down after 1, 2, 3 or 4 attacks or not at all. Which of the rolls are done with advantage and which have disadvantage?

Balance

Checking with a little program, which version yields higher expected damage.

Some restrictions for the sake of simplicity:

• 2 attacks: One standard and one off hand
• crits are ignored
• The roll needed to hit is known before
• The the following results are possible (decreasing order of preference):
  1. Both attacks hit
  2. The attack with the main hand hits
  3. The off-hand attack hits
  4. None of the attacks hit
• Damage with the main hand attack is 7.5 (1d6+4) and 3.5 with the off-hand attack (or 7.5 for the standard fighting style)

$$ \begin{array}{|r|l|l|} \text{minimum roll to hit}&\text{expected damage 2WF}&\text{expected damage your 2WF}\\\hline 3&13.5&10.89375\\ 4&12.75&10.76\\ 5&12.0&10.5725\\ 6&11.25&10.33125\\ 7&10.5&9.81625\\ 8&9.75&9.28375\\ 9&9.0&8.73375\\ 10&8.25&8.16625\\ 11&7.5&7.58125\\ 12&6.75&7.005\\ 13&6.0&6.44625\\ 14&5.25&5.905\\ 15&4.5&5.38125\\ 16&3.75&4.875\\ 17&3.0&4.395\\ 18&2.25&3.94125\\ 19&1.5&3.51375\\ \end{array} $$

Since the average chance of hitting is usually above 50% (minimum roll 10 or below in the table) the results seem less effective than the standard 2 weapon fighting. For targets that are extremely hard to hit, your version of the fighting style can be drastically superior to the standard 2 weapon fighting style.

Conclusion

Dealing less damage on average just to one additional time in a fight and making your life more complicated with rolling everything before the first attack doesn't seem like a good idea to me. In the end only a playtest can tell you, if the rules are enjoyable, but the amount of special cases you need to consider will probably result in rules that are more trouble than they are worth...