I'm getting pretty close to wrapping up a campaign where the highest damage dealing character in the party was a Sharpshooting Fighter, who in combination with the Crossbow Expert feat, was regularly dealing upwards of 100 points of damage per turn in the levels 11-16 range, not including Action Surges.
For reference, the Sharpshooter feat, rules-as-written (Player's Handbook, pg. 170), is a feat that confers three benefits:
- The character no longer takes Disadvantage when attacking from the "Long Range" of a ranged weapon
- The character ignores the effects of half cover and three-fourths cover on targets they attack
- The character may, before they make their attack roll, choose to take a -5 penalty to the attack roll, gaining a +10 bonus to the damage roll if the attack successfully hits
In the campaign in question, the fighter's high damage output wasn't a problem: the campaign was designed as a generally high-power-level game, and while his damage was easily eclipsing the rest of the party, the rest of the party all consisted of spellcasters whose versatility kept them from being irrelevant—and who, under the right circumstances, were plenty capable of bursting out large amounts of damage with a well placed spell.
But, in preparations for the next campaign, I am seriously considering making an adjustment to the feat to reduce its overall power level.
The modification/nerf I am making, in its totality, is that instead of being permitted to take a -5 penalty to the attack roll in exchange for gaining a +10 bonus to the damage, the modified version of the feat will allow a character to take a -5 penalty to their attack roll in exchange for gaining a +5 bonus to the damage. The other features of the feat would remain as-is.
My logic in making this change is that, in my experience, a single point of damage is usually still worth more, in terms of overall average damage output, than a single point modifier to the attack roll. My intention is not to ban the feat or make players feel bad for taking it, but rather to just dial back its power to make the moment-to-moment decision-making of whether to use it more important, and to make the macro-level "should I take this feat?" question less obvious.
So my question then is, what are the mathematical consequences of this change compared to the official version of the feat, and if this feat were offered at a table where you were planning to play a ranged/archery focused character, would this modified version of the feat still be worth taking or would the drop in power level make it too weak to justify taking this feat as part of your build?
Best Answer
For Sharpshooter, only two numeric variables matter: to hit and target armor class.
The formula for the probability an attack hits only has two variables:
$$P(hit)=\frac{21-AC+HIT}{20}$$
Where AC is the target's armor class and HIT is the character's bonus to hit with the attack. Now, the damage die size of the weapon used can change when taking the Sharpshooter penalty is worth it, but in the question we're talking about a Crossbow Expert, meaning hand crossbow, which has a d6, so die sized will be fixed at d6 for this analysis.
The question first examines an 11th to 16th level fighter, who gets three attacks per action plus one bonus action attack via Crossbow Expert. Notably, the number of attacks per turn doesn't not affect when to use Sharpshooter. An 11th level fighter can feasibly have +11 to hit with a hand crossbow (+5 DEX, +4 Prof, +2 Archery Fighting Style). Here's how the numbers shake out for this fighter:
SS (-5/+10) beats out taking the base attacks for ACs 22 and down, SS(-5/+5) beats out base attacks for ACs 18 and down. And even then, the damage boost from SS(-5/+5) is small, with the difference being only being about 3.5 damage at AC 15, about half the boost from SS(-5/+10) at that same AC. So in a Tier 3 campaign, we're looking at a pretty small boost for lower AC targets, with SS(-5/+5) being a net negative for AC 19 and up targets.
For a lower level fighter, SS(-5/+5) is even less generally useful. Taking a 5th level fighter with only +8 to hit (+3 DEX, +3 Prof, +2 Archery Fighting Style), the damage boost from SS(-5/+5) starts to become irrelevant much faster:
This time, SS(-5/+10) beats base attacks for ACs 19 and down, and SS(-5/+5) is only relevant for ACs 15 and down, and even then, it isn't much. Even at AC 10, SS(-5/+5) only yields around a +3 boost in damage per turn, with the bonus coming out to less than half a point at AC 15. On the other hand, at AC 15, SS(-5/+10) averages an additional 7 damage, and at AC 10, an additional 14 damage.
This takes Sharpshooter down a peg from "Must Take" to "Pretty Good".
Mathematically, your nerf makes the damage boost highly situational. Before, the damage boost was huge for lower AC targets, non-negligible for mid-AC targets, and a net negative only for very high AC targets. Now, it is really only good for picking off very low AC targets, which might be commonplace in a Tier 1 and Tier 2 campaign, but the boost fades from relevance as lower AC targets become increasingly rare.
That said, the other two bullets are still great features, especially for a Crossbow Expert. The vanilla hand crossbow has a measly 30 foot normal range, and Sharpshooter takes that out to 120. This feature alone makes the feat attractive for a Crossbow Expert. Together with ignoring 1/2 and 3/4 cover, and the situational damage boost makes your version of the feat still viable for Crossbow Experts, but not quite the "must have" the original version is.
To give a concise stamp on this one: probably balanced, ready for play testing.