Sure, maybe you can find a turn to stick an aura and get an extra 3/1, but with Shivan Fire and Vicious Offerings running around Valduk can quickly turn into ashes
This is a deck where Firesong and Sunspeaker could really shine in the other 99, which means I will address the elephant in the room: Firesong and Sunspeakers exclusivity
We could use it to find all cards that deal any amount of damage
Sure, Parallel Lives and Anointed Procession are cute, but what happens once that non-aura Enchantment is out of the yard and has already become two weird 3/3 Black Zombie creatures that are also somehow also Deadbridge Chants
That ability may still be on the stack, or it could have resolved, failed to resolve, been countered, or have been removed from the stack some other way
If you have counterspells, you probably want to leave mana open to cast them on your opponents' turns