D&D 5E Great Weapon Mastery - once more into the breach! (with math)

Hello

Context: This is a re-post of a discussion in another thread about clerics where quite frankly it derailed the tread, and I though I should repost here. I did all this work after all These calculations were done at the request of [MENTION=12731]CapnZapp[/MENTION] .

A lot of people feel that the feat Great Weapon Mastery is broken - much too overpowered. The reason why is that the - 5 penalty to hit is "trivial" and can easily be circumvented with advantage, or other to hit boosters (such as Bless). Personally I felt it might have been a bit too strong, but I was annoyed that few people were doing the *proper* comparison. You shouldn't compare normal attack vs GMW + advantage. You should compare normal attack + advantage to GMW + advantage! Otherwise the comparison wasn't "real".

I never bothered doing the math though until later, when I was creating a level 11 Barbarian. I feel it's important to do these exercises with "real" characters that are actually going to be used. So here comes Lal Qualandar, a barbarian-hermit (a sort of wandering mystic), featured in [MENTION=20323]Quickleaf[/MENTION] 's game. With the feat, his strength will be 18. Without, it will be 20, so there is an opportunity cost to taking the feat. It should be noted that he has a +2 great axe.



As you can see, GWM is good but it is *nowhere* as good as +10 to damage per attack, even with advantage

Post 2 to follow, if I put more than one table per post it's messed up - the story isn't over!

At this point, it was pointed out that I was doing it wrong - a well optimized character, such as a battlemaster, would have ways to "ensure" a hit such as the precision maneuvre, or the lucky feat. NO ONE had done this math, apparently.

Fair enough. So let's dig up another PC then - we aren't going to use made up examples (baring the fact that all PCs are made up...) but one that was intended for play. Alas, Rodrigo di Castalone never saw play, but he exists. He was meant as a rapier fighter however, but whatever, out with the rapier, in with the greatsword, out with the dex, in with the strenght. As requested, he does not have a magical weapon (interestingly, Rodrigo was obsessed about finding a magical blade...)

Rodrigo is level 7. Featless Rodrigo has 20 strength, while GWM Rodrigo has strength 18 - there is an opportunity cost here. So let's do this in steps (easier to manage attachments), and first compare Featless Rodrigo damage vs GWM Rodrigo without any special maneuvers. To make my life easier, I've used a smaller spread of AC values, but it's still illustrative.



As you can see, it's *okay-ish*, at best. The lack of magical weapon is really telling here. But precision should help here! Stay tune for the results of that.

P.S. please note that this once again ignores critical hits

So for this next table I calculate the impact of using a precision battlemaster maneuvre on an attack done with GWM. And it looks like [MENTION=12731]CapnZapp[/MENTION] is correct, it *realllly* makes a big difference:



BUT if we stop here, we will make the error I mentioned at the begging - we are not comparing the same things! Featless Rodrigo, he too has maneuvers, and these also have to be considered - it's not fair to compare GWM + maneuvers to normal attack without maneuvers

Here we are, the final countdown. Thank you for your patience.

So featless Rodrigo went "wait a minute, I have maneuvers too! Ha-ya!". But instead of using precision - he already is pretty good at hitting - he decided to use a maneuver that gives him *damage*. And well... suddenly GWM isn't so awesome anymore. I mean it's still decent, but it's not that stark.




It's also worth noting that several of the damaging maneuvers only have to be declared when you hit - so there is no chance of a "wasted" maneuver dice. A precision maneuver may fail (ie you need 3 more to hit but you roll a 2 on your d8). Furthermore, several of the damaging maneuvers also can impose negative conditions on the target - fear, being tripped etc.

At this point someone may say "but what if GWM Rodrigo uses precision and damaging maneuvers!" OR a bard inspiration, the luck feat etc etc etc. Sure. But you always have to compare that to featless Rodrigo *also* using more maneuvers, bard juice etc etc etc. And that is THE KEY ELEMENT that seems to be always missing from these analysis - we need to compare like with like. First people were comparing base attacks to GWM + advantage. I showed that if both had advantage, the difference wasn't so great. Then other bonuses got piled on - but again, if you compare PROPERLY it's not such a big difference.

There also comes a point where it's ridiculous to pile too much stuff into a single attack. For example Rodrigo could have had the lucky feat and used it too. Sure but now Rodrigo only has 16 strength... and wouldn't you want to spread out those bonus rolls? Or better yet, keep it for something more important than a single attack, like a key skill check or save?

So in conclusion, I used to think that GWM was OP - maybe not as broken as some made it out to be, but still too good. Now... maybe it's OP?

Nothing like beating a dead horse. With a great weapon.

As I've mentioned earlier, when you account for the bonus action attack you really push the feat into being far, far better than without having the feat. That part of the feat is always active and works with any melee attack.

At the extreme, if you have a Champion Fighter with Advantage (say, from a raging wolf barbarian or tag-team with a PC with Shield Master feat) and you have two attacks then you get a bonus attack just from critical hits 34.4% of the time. That's crazy.

Target AC: 15
GWF Champion with GWM feat (but not using -5/+10), two attacks, level 7, and advantage will do 29.1 DPR.

GWF Champion without GWM feat, two attacks, level 7, and advantage will do 27.4 DPR.

GWF Champion with GWM feat (but not using -5/+10), two attacks, level 7, no advantage will do 20.7 DPR.

GWF Champion without GWM feat, two attacks, level 7, no advantage will do 20.4 DPR.

Feat, Advantage ----- 29.1
No Feat, Advantage - 27.4

Feat, No Advantage ----- 20.7
No Feat, No Advantage - 20.4

Yes, you saw that correctly. Even without using the much attacked -5/+10 portion of the feat the lowly Champion Fighter and his much-maligned expanded crit range does more DPR with the feat than without it even if his STR is only 18 no matter what. (I'm not going to do the math, but I think he does more damage no matter the target's AC)

Oh, and this is assuming the creature has infinite HP so the Champion never gets an extra attack from bringing an opponent to 0 HP.

Champion Fighters with GWM in two-man teams with someone who can give them advantage is abusive.

I been saying all along I have GMW etc in all my games pole arm with GWM etc and it has broken nothing. All my groups have slightly higher stats because we do 4d6 drop the lowest and they do three sets and pick one. I also found that when you start hitting higher AC it becomes even less effective. I call it the big # effect just like people in the old MMORPG games always thinking the big hit was the best build then we started breaking out dps and using animation times etc and figured out optimal attack chains was not always what people assumed what the best ones were.

I have feeling you didn't even bother to read my post. Now, it's only for Champions with an expanded crit range but there is never a point where GWM is less effective (at least for damage) than without it even if you NEVER use the -5/+10 part. Because if you think the AC of the target is high you just don't use the -5/+10 portion.

Also, under your system of rolling for ability scores you'll likely have a higher starting stat so that makes GWM even better. Sure, it won't "break" the game but that's a terrible bar to judge against.

I just did some math. Against an AC 18 opponent and giving a level 8 Champion with 20 STR a 20% chance of knocking a foe to 0 HP with any hit that isn't a critical, the Champion will do between 8-34% more damage depending on whether he has advantage or not or chooses to use the -5/+10 part of the feat or not.

Simply having the feat and never ever using the -5/+10 portion and never having advantage gives him 17% more damage. Though at that point he might as well take PAM instead.

Well it should be better to have the feat, whether you use the -5/+10 regularly or not, every feat taken should improve the character in some way depending on how the character is built. The question isn't "Is having GWM better than not having it?" It's "Is GWM grossly overpowered?" and apparently the answer to that is, no.

Belay my last line. GWM for my example PC, even if you never, ever use the -5/+10 part of the feat still outdamages PAM (not counting getting a first strike in).

That's how good GWM is. You can remove the part of the feat people complain about most and it still does more damage than an entire feat that people complain about - PAM.

EDIT: I guess someone needs to come up with an idea of how much extra damage a feat should do. Is boosting damage 20% reasonable for a feat? 25%? A GWF Champion simply adding +2 to his STR at level 4 increases his damage 16% versus an AC 15 foe, for example.