Fighting Styles

Ignoring unarmed combat for the moment, there are broadly speaking four possible fighting styles a character can adopt in melee, depending on what he has in his 'off' hand:

• Single-weapon style - the character has an empty hand.
• Sword-and-shield style - the character has a one-handed weapon and a shield.
• Two-handed weapon style - the character is using a single two-handed weapon.
• Two-weapon style - the character has a weapon in each hand

Now, of these four, the first is clearly inferior. The only thing it really has to offer is versatility, in that the character can use his off hand for, well, whatever comes up. But other than a potential (minor) defensive boost gained by turning flank-on to his opponents, there's not a lot to recommend that style.

Which is fine, IMO.

However, ideally, the other three styles should ideally be roughly balanced. (Though it's worth noting - if a character invests feats/powers/whatever in a given style, then it's fair for that style to be strictly better than the alternatives.)

Now, it's pretty obvious what sword-and-shield style offers - the character gains defensive bonuses as a result of carrying that shield. And the game reflects that neatly, as the character has a higher AC and can use the "Shields Shall be Splintered" rule.

Likewise, it's pretty obvious what two-handed weapon style offers - the character gains offensive bonuses as a result of using heavy weapons. And the game also reflects that, in the higher damage offered by two-handed weapons (1d8 for a longsword vs 1d12 for a greatsword).

But two-weapon style...

My current thinking is that the benefit of two-weapon style is versatility - the player can choose whether to use those two weapons defensively or offensively, potentially switching each round on his turn. And, of course, neither approach should be quite as good as the corresponding "pure" style. So, when used defensively, the character gains a single attack at a -2 penalty, but gains a +1 bonus to AC.

Conversely, when fighting offensively, the character gets two attempts to land a single blow. That is, the character makes two attacks (at his better attack bonus, with a -2 penalty). If either or both of these rolls indicates a hit, then the character has landed a blow. At this point, he can choose which weapon actually hit, and roll damage accordingly. (But it's important to note that this is not the same as having advantage on every attack - I expect Sneak Attack to trigger on advantage, and don't want TWF to become a no-brainer choice for every Rogue!)

Of course, it's entirely likely that the game will also have a bunch of talents that apply to the different styles, or apply to the styles differently. But that's for another day...