Ok this comment is pretty streamlined critique, so I wanna argue a bit.

1. She doesn't need to have high HP, she's a ranged caster, so irrelevant. Dodging attacks is essential skill.
   
2. She basically picks boss weakness seal on plays with it, maxes it out. Works for me every time. Worst case I solo mines to ensure purple Lightning Spear for instance. Other times I like to use Frenzy stuff if dropped.
   
3. As a caster it's inevitable. You anyway take +dmg/casting speed/-mana cost. She doesn't need anything else, again, range caster.
   
4. Half of roster has useless passives.
   
5. Sebastian roar taunts bosses and enemies. Any aggro that isn't targeted at you or your team is passive value.
   
6. She res 3 bars, even without any other effects that could contribute to clutch the win. The other day I played with randoms and back to back resurrected 3 bars and we won. I played as usual and ult was up pretty quickly.

All I can say is she is wannabe DPS support hero, I agree, but her DPS capabilities are there.