I don’t think it’s based on the best player stats, they’re just the best abilities by far so the “best” (as in, highest level doing the hardest content) players use them exclusively. Even post-nerf, I ran an expedition and my Blighted Rounds accounted for 5 million damage. My blighted turret – which was deployed the entire fight and I’m specced/modded into it – clocked in at 112,000 damage. Toxin effects added up to another 200,000. The magic ammo abilities are still busted in how much better they are than anything else.
Put another way, a blighted round with my LMG hits from 3,000-5,000 damage and I have a 225 round magazine. If I use the Minigun skill, it hits for 900 damage BUT it gets mitigated by armor so it’s much lower than that, especially on Elites. It also has something like 120 bullets before it runs out (double that with the correct mod). However, I move slow, can’t dodge/use cover, etc. My blighted rounds also hit everyone in the area for 50% of the bullet damage and I go through an entire level without reloading my magazine so I never run out of blighted rounds. Meanwhile, minigun is on a 40s cooldown or so.
My original build was going Ordinance and relying on minigun, grenade, and the pain launcher but blighted rounds is without exaggeration 10x better at this point. I’m sure it’ll be addressed, but it’s a little unfortunate right now. I feel pigeonholed into it because Expeditions (stupidly) are timed trials, so if you’re not outputting max DPS at all times you’re crippling yourself.