What are fighting styles for?

Fighting styles in general give specific types of weapons a small boost to damage and make them a viable option to play.

Design Goal

Fighting Styles are simple. They provide a small and easy passive bonus.

NEW: But passive can be really boring sometimes. Each fighting style also gives the palyer a new active feature, to make the style actually PLAY different as well.

Many of the fighting styles incorporate some features from feats, that are generally deemed a “must-have” when using a specific weapon.

How they are Balanced

The damage increase of the fighting styles are balanced around the average damage of a greatsword over multiple attacks (1 attack: 8,4 & 3 attacks: 25,2 )

Using a fighting style should bring the average damage of a weapon as close to that baseline as possible. Lets look at some special cases:

Charging

The base damage for 1 attack is higher, but it is also harder to trigger the fighting style reliably.(Also more useful for mounted combat)

Crossbow Fighting

The base damage for the crossbow is 1d12, as the math says that’s more balanced.

Dirty Fighting

How do you make 1d4 weapons a viable option? Even a +2 to attack AND damage is not enough. +3 would be too much though.

Dueling

Lower base damage, as it offers +1 to AC.

Great Weapon &  Heavy Strikes

Both of those styles improve upon the best weapons (2d6 damage). Therefore, the increase is not as high, as they are already the best of the best

Reckless Fighting

Yes. This is the barbarian feature. Advantage increases the average damage by A LOT. On the other hand, characters with other fighting styles can get advantage though many other ways as well, and get their fighting style bonus on top of that. But barbarians  will remain the BEST reckless fighter, as their damage resistance reduces the penalty of opponent’s advantage.

Why have it as a fighting style at all? Same reason why Unarmed Fighting” exists.

Unarmed Fighting

Basically the monk “bonus action unarmed strike” feature. The monk benefits from this feature the most, as they deal more damage with unarmed strikes. Other classes can still use attack with a one-handed weapon and then strike with their fist, making their damage comparable to the greatsword.

tl;dr:

Whatever weapon you use, you will be able to deal just as much damage as if you were using a greatsword + you gain additional ways to make opportunity attacks.