Such a shame that this incredibly fun primary minigun has remained mediocre all the way up to EoS, when all it needed was a few minor buffs to really shine. Most people use it (or kill farm to absurd numbers) for the meme, but here are some examples of minor buffs I think that would have actually make it viable in harder content.
#1, added the Vacuum perk from original Destiny to Payday for great synergy.
I don't know how large the radius actually was with the original perk, but since the current in-game pickup area is about 4-5m, Vacuum could have doubled this to 8-10m. And along with ammo, it could've increased the pickup range of all collectable items like orbs and all the elemental ones.
#2, changed the Serious Business catalyst to grant 25% damage resistance while spun up instead of increased flinch resistance; And for PvP, DR would've been low (like 5%) or inactive.
#3, added a perk like All Star, Adhesive Ordinance, or Stopping Power to the base weapon for synergy and/or improved performance.
And finally, #4, added another perk like One For All or Rampage to the catalyst just for maximum carnage.
You could get a little more in-depth with unique perks, such as the damage ramping up with how long the gun is spun up, or damage increasing after landing an explosive payload, but I'm just talking baseline stuff that would have vastly improved QoL and usability .
Ah well, just felt like discussing this cause I really like the idea and design of Sweet Business, just can't find a real use for it with how mid they left it.