Re: Fatebringer, new Raid weapons are technically better. Word of Crota does slightly more damage per bullet and has a significantly higher rate of fire. These two criteria combined make for higher DPS on WoC, which moreover has Explosive Rounds like FB. This perk (in PVE) doesn't change your crit damage (it's split between a reduced crit and an explosion that exactly matches the crit reduction) but offers far better damage on body shots.
All things considered, WoC is great and on paper better than FB. But at least in my opinion no gun feels like FB. Not WoC, not Hawkmoon, nothing. Outlaw and Firefly on a Hand Cannon is just too perfect. It has that umpgh, I can't explain it. It's subjective, I wouldn't argue that perk combo makes FB the de facto best primary in the game. But for me and others, it will feel that way until something comes along with that sensation.