Like DalzK said, it's not like this is about 1v1. I see your point about assassins though..
But Sedna (the tigergirl.. mm..) isn't that op 1v1. I don't remember the exact numbers, but I don't think Pounce deals 1000 damage, it's less. You both have to pay mana for your skills, it's not like Sedna gets free heals, Healing Wind excluded. You as Torch Bearer also have more damage skills than just fireball, can have stun, and such. TB is also a ranged demigod, Sedna is not (though se can close the distance, but still).
Sedna is hard to kill, but not unbalanced even for 1v1 I believe.