I think you're missing the part where rogues are supposed to be a T2? There has definitely been a disconnect in t1 and T2 over past several years. Where everyone was basically a t1. Or maybe I'm missing it. Maybe all the "DPS classes" should be viable for t1.
But sure let's 2x-3x the damage of the 2nd highest parsing ability on the class..
When debuffs were meaningful, and T1 classes didn't have exceptional utility (see assassin epic, warlock potency buff/venemous runes), the T2 distinction made sense for rogues. Sure swashes still have an exceptional raid-wide buff, but is that alone worth a 50% hit in DPS from a warlock or assassin, given that only one swash is required in raid for their buff? So anyone claiming that swash DPS
should be bad, I think are operating off old assumptions? I thought exaggerated tiering for raid DPS was a problem the community generally agreed upon.
Brigs are a different story altogether (at least from what I've seen), they need a lot of love to bring them into the same discussion. But that's a topic for a different sub-forum.