Maybe I'm being pedantic, but increasing damage doesn't sound like improving accuracy too much, -5 to hit sure doesn't. I mean, you take one of these feats, but monsters of lower level can still hit you, you can still hit monsters of higher level. Bounded Accuracy seems intact. Indeed, a -5 feat seems designed with the idea that Bounded Accuracy will let you keep hitting in spite of it, since ACs don't advance rapidly in lock-step with levels.
OK, that's different. But +1d4 certainly seems innocuous. You can roll a '1,' and miss an easy target, you can roll a 4 and hit a difficult one. Seems to leave things wide open.
Simple example.
Wizard casts Hold Person.
AC 18 foe fails save.
11th level great weapon Fighter would normally hit a held AC 18 foe for 3 criticals for about 65 points of damage. DPR is about 54 points of damage. There is a slim chance that the Fighter misses, but with advantage, it's fairly uncommon at +9 to miss, even without a magic weapon (most PCs have at least a +1 weapon by level 11, but we'll ignore that).
With GWM, the same 11th level great weapon Fighter would normally hit a held AC 18 foe for at least 3 criticals for about 95 points of damage and could possible critical him 4 times. There is a greater chance that the Fighter misses each time, but overall his DPR goes up to 73.
A 35% increase in damage without magic items, without Bless, without other buffs. Just GWM. Once other synergies come into play, it increases a lot faster.
Just adding Bless to the equation means:
60 DPR vs. 92 DPR
The normal case increased by 6 DPR, the GWM case increased by 19 DPR (53% more damage now).
Against a lower AC foe, the DPR delta is considerably greater. Same with a magic weapon.
The point is that it is not that difficult to give a melee PC buffs, advantage, and other benefits.
Paladins get one fewer attack per round, but they can load up on a lot of damage with Smite and such. Granted, that is using non-renewable resources, but in a tough fight against a powerful high AC foe, the Paladin or Fighter is doing 50% more damage than the Rogue (who is also doing a critical with sneak attack damage against a held foe for about 52 DPR). Bless makes the Rogues DPR go from 52 to 53.
So we have:
Fighter without GWM: DPR 54
Blessed Fighter without GWM: DPR 60
Fighter with GWM: DPR 73
Blessed Fighter with GWM: DPR 90
Rogue: DPR 52
Blessed Rogue: DPR 53
Granted, foes are not going to be held a lot for the auto-criticals, but there are quite a few ways to get advantage (prone, faerie fire, blinded, etc.).
