Helldritch
Hero
Let us assume 20 in relevant stat (dex or st)
Great weapon style: Battle axe: 1-12, reroll any 1 or 2 so we can safely assume about 3-12. This gives us 8 to 17 damage with an average of 12.5 per hit. Our Great Sword master is a bit better off. 2d6 dmg reroll any 1 or 2 once per attack. Lets assume 1 roll every time. This means about 3-6 + 3-6 or 6-12, add in the stat and you get 11 - 17 or an average of 14. The great sword is clearly the better here. All great weapons should be on the 2d6 attack damage to justify a change in styles.
Dueling, lets go for the long blade option: 1d8 (long sword, or rapier) +7. This means 8-15 or an average of 11.5 per attack. The great axe user only gains 1 pt worth of damage over the dueling character but the great sword master gets about 3 more. On one attack it is not much, over 3 attacks it is 9 points of damage in favor the great sword master. At four attacks, it means 12 more points of damage. As much as one attack from the dueling character. The cost is two points of AC from a shield. If the dueling character is based on dexterity, this means that the AC advantage from dexterity is almost lost if we assume medium armor. Max AC bonus is +2 for such an armor so the maximum AC will be 19 with a shield. Unless the character wears plate and accept a penalty of movement (assuming strength is low...) dueling only wins one point of AC vs a great weapon style. So a dex based character loses a bit by using dex for dueling (barring multiclass character concepts like fighter/rogue).
If we take into consideration criticals...
The great weapon style double the dice (and let's forget that axe please). Lets assume one roll 3-6 + 3-6 + 1-6 + 1-6 + 5 this will give us 13 to 29 dmg for an average of 21 dmg.
The duelist will do 1-8 + 1-8 +7 for 2-16 +7 or an average of 16.
So duelist is not really out balanced. The benefits of a +2 in AC is quite good as most monster in the MM will have a relatively hard time hitting an AC 20.
I personally think that the problem comes from the 1d12 great weapons. The reroll of one dice is not enough to warrant using one of these. Glaive and Polearms give reach so the lessened damage is not that bad for this advantage. The great axe gives nothing for the loss of damage vs great sword. Either the great axe is bad, or the great sword is too good. So let's give the axe an edge. Why not introduce a new damage type:
Cleaving: A weapon with this property counts both as a slashing and blunt weapon. When it comes to take into account resistance or vulnerability to a damage type this weapon takes the most advantageous one for the user.
So if a creature has resistance to blunt or slashing, the axe does full damage in either case. If the creature has a weakness to one type of damage, the axe damage is increased. Not a great advantage but an advantage that justify only one die of damage. Since many enemies of dwarves like to use undead skeletons (orc shaman do animate fallen foes and friends) it would be a small justification.
Great weapon style: Battle axe: 1-12, reroll any 1 or 2 so we can safely assume about 3-12. This gives us 8 to 17 damage with an average of 12.5 per hit. Our Great Sword master is a bit better off. 2d6 dmg reroll any 1 or 2 once per attack. Lets assume 1 roll every time. This means about 3-6 + 3-6 or 6-12, add in the stat and you get 11 - 17 or an average of 14. The great sword is clearly the better here. All great weapons should be on the 2d6 attack damage to justify a change in styles.
Dueling, lets go for the long blade option: 1d8 (long sword, or rapier) +7. This means 8-15 or an average of 11.5 per attack. The great axe user only gains 1 pt worth of damage over the dueling character but the great sword master gets about 3 more. On one attack it is not much, over 3 attacks it is 9 points of damage in favor the great sword master. At four attacks, it means 12 more points of damage. As much as one attack from the dueling character. The cost is two points of AC from a shield. If the dueling character is based on dexterity, this means that the AC advantage from dexterity is almost lost if we assume medium armor. Max AC bonus is +2 for such an armor so the maximum AC will be 19 with a shield. Unless the character wears plate and accept a penalty of movement (assuming strength is low...) dueling only wins one point of AC vs a great weapon style. So a dex based character loses a bit by using dex for dueling (barring multiclass character concepts like fighter/rogue).
If we take into consideration criticals...
The great weapon style double the dice (and let's forget that axe please). Lets assume one roll 3-6 + 3-6 + 1-6 + 1-6 + 5 this will give us 13 to 29 dmg for an average of 21 dmg.
The duelist will do 1-8 + 1-8 +7 for 2-16 +7 or an average of 16.
So duelist is not really out balanced. The benefits of a +2 in AC is quite good as most monster in the MM will have a relatively hard time hitting an AC 20.
I personally think that the problem comes from the 1d12 great weapons. The reroll of one dice is not enough to warrant using one of these. Glaive and Polearms give reach so the lessened damage is not that bad for this advantage. The great axe gives nothing for the loss of damage vs great sword. Either the great axe is bad, or the great sword is too good. So let's give the axe an edge. Why not introduce a new damage type:
Cleaving: A weapon with this property counts both as a slashing and blunt weapon. When it comes to take into account resistance or vulnerability to a damage type this weapon takes the most advantageous one for the user.
So if a creature has resistance to blunt or slashing, the axe does full damage in either case. If the creature has a weakness to one type of damage, the axe damage is increased. Not a great advantage but an advantage that justify only one die of damage. Since many enemies of dwarves like to use undead skeletons (orc shaman do animate fallen foes and friends) it would be a small justification.