Most players and DMs know the following feats: Great Weapon Master and Sharpshooter. Both feats have the ability, to take a -5 penalty on your attack roll to add +10 to the damage roll. Some DMs have a bit of trouble with these feats.
- Since most ACs of monsters aren’t that high, even with -5 to hit it’s still seems pretty accurate
- Classes who have reliable means of gaining advantage (like the barbarian) or ways to grant their allies advantage (like a lot of spellcasters with spells like Guiding Bolt, Faery Fire, etc.) or those ways to grant +hit (like the Bless spell or a Battle Master’s Precision Attack maneuver) trades the intended reliability to outright more damage potential
- Both feats overall (and especially that trait) boosts the overall combat ability of two builds (ranged weapon and two-handed weapon), while other weapon builds seems to have only subpar feats (due the more specific use of Shield Master, the somewhat lacking feeling advantages of Dual Wielder and the seemingly lack of something, which enhances your one weapon, one hand free style [try Tavern Brawler; one of the best ways to be a defender, imo])
OK, I have to admit: These feats are really good. But after seeing both in action, I don’t think, that they’re broken. It only seems that way at first, since at the beginning of a campaign, those +10 damage will kill monsters outright, however, after getting around 5th level, the monsters won’t be taken down that easily and . And remember, bounded accuracy actually makes it so, that the to hit chance decrease by 25%, unless the enemy’s AC is outright horrible.
But the farther you go, the less it means in math. At least for some classes. Of course the statistic will change, with different means to give your damage. Let’s compare the paladin and fighter: While the fighter gets another attack at 11th level, the paladin does more damage with his attacks. So the fighter gets more reliability (which means he can take the -5 while having a buffer attack left), while the paladin begins to want more of his attacks actually hit (especially under Divine Favor or another damage buff). Even though the math is the same (-5 to hit, +10 to damage), the paladin player wants all his attacks to hit, while the fighter will think, that one attack missing won’t negate the +10 damage most of the time. A ranger (hunter) with Colossus Slayer will rather try to get his bonus damage done first and then switch to the more unreliable but powerful attacks afterwards, to make most of this subclass trait.
What really makes those both feats shine early on are the other effects. Like making an attack as a Bonus Action when scoring a critical (say hallo, Champion)/killing one or ambushing enemies by shooting from far, far away. Of course these don’t seem all that powerful, until you see it in action. With the +damage the GWM is able to kill a lot of early enemies and trigger the bonus attack, while the sharpshooter can make more shots by retreating.
So, how can I think, that these feats aren’t broken? Simply, because I learned how to soften them without ruling. A special way to ensure it is: More enemies. More enemies makes more damage less important than reliability, since you need to take some of them out, otherwise the bounded accuracy will kick your ass.
As long as you don’t place them that all of them will be spellslinger-fodder, your weapon users will get a hard time, since even with all the damage and all the extra attacks, there will be more rolls, which makes a combat more statistically stable. And the joke is, that even then the XP won’t be as much, since using more enemies makes a encounter more difficult, so you won’t need as much to make it challenging.
Another reason why I don’t go WTF is because most of the real ‘unbalanced’ stuff comes from resources (Superiority Dice), risk (Reckless Attack) or teamwork. And I think teamwork should be strong, playing a game together is one of the reasons why you play D&D in the first place. Even though you should disrupt it occasionally. in the Forgotten Realms are places, where spells won’t work like the caster might think (weaveless areas and spellplague) or the setting makes it impossible to pull off (like balancing on a 2 foot width bridge).
Conclusions
If you really think, that those two feats are bad, you should simply not allow them. If you think, that the -5/+10 aren’t balances, either allow a -5/+5 variant for all other characters or simply switch it with +1 STR for GWM and +1 DEX for Sharpshooter, so the other effects stays in place.
Or maybe you’re like me as a DM and customize some of your enemies to have those feats as well or increade their accuracy/damage otherwise, so the combats will be quicker without loosing their menace.