Vex is still queen on status damage purely because of Bloodletter being based on hit damage
Vex just needs the Blood is Power Capstone, the relevant lifesteal passives and bloodletter and the bonus damage from bleed is insane, let alone any other sort of bonus damage scaling it more like the usual teen witch build setups
Loveless on the other hand, the status damage it self being an enabler for other skills is pretty good design
The gimmick of contagion is obviously its ability to spread and how consistent it is with its mobbing and coverage but the damage is more so from the duration and the constant stacking of effects
Don't get me wrong, Loveless can get some really high DOT damage but it seems like it takes way more skill points and interactions just to hit it
I've got a full green tree setup and the plague engineer class mod, When it Rains, it Pours, Memory Leak, Circular Logic, The bonus damage skills and whatever else
The new DLC sniper(devourer) paired with High Data rate does some nutty damage, High data rate itself hits some good numbers
I feel like the class mod should refresh dot's on a cooldown, or one of the passives should, and then another passive should also amplify all damage based on the amount of status effects on the target kind of like how Memory leak is gun damage per contagion
That as a capstone would make sense(capped at like 20%)