In general I think the bonus action economy is ok.
It is just some classes that should do well do not because it is triggering from taking the attack action and because it competes in an unfavourable way with a different feature.
Good: cunning action/twf.
Bad:
ranger in general with hunter's mark
- beastmaster
- hunter lvl 11 feature
- horizon walker
I also don't like that there is no penalty for using two weapons as a wizard etc.
So my solution would be something along the line of:
- twf needs an ability to be used.
For example:
Cunning action gives twf as it is now.
Twf fighting style allows twf as a free attack with your offhand weapon doing no stat bonus to damage.
You need to check if you allow both features at once. But since both weapons need to be light then it seems ok.
TWF feat changes to:
You may use a bonus action to attack with an off-hand dagger.
You gain +1 AC
You can draw 2 weapons as part of the attack action.
Note that it overwrites the rogue feature with an attack that does stat bonus to damage.
My fix that we use for TWF at our table is this:
Main and Off-hand Attacks
• When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can make +1 additional attack with a different light melee weapon that you're holding in the other hand. All attacks are made at disadvantage.
• If either weapon has the thrown property, you can throw the weapon, instead of making a melee attack with it.
Or
• You can add the damage die for the second weapon to the damage die of the first weapon for each attack. Modifiers are applied as normal to the regular attack.
Two-Weapon Fighting (Fighting Style)
• You gain +1 bonus to AC while you are wielding a separate melee weapon in each hand.
• You no longer attack with disadvantage when attacking with weapons in both hands.
Dual Wielder (Feat)
• You can use two-weapon fighting even when the one-handed melee weapons you are wielding aren't light.
• You can draw or stow two one-handed weapons when you would normally be able to draw or stow only one.
• For each attack granted by the Attack action that you attack with a melee weapon in one hand you can make an additional attack with a different melee weapon you are holding in the other hand
*Rogues using a light weapon in offhand do not suffer disadvantage on attacks while two weapons fighting. (Gets around the issue of rogues not having the two weapon fighting style).
Also these changes only apply to melee weapons and the associated styles/feats. Ranged attacks and cross bow expert still use the bonus action to fire the extra attack.
