Pointed Discussion

Does the demon make it worth that much more mana than Innocent Blood?

Yes.

Not very reliable, unfortunately, because each player can simply sacrifice a tiny creature to minimize the Demon. It'd be a whole different story if the spell let you target a creature to kill. At 6cc, It's easier to use IPhyrexian Rebirth, which let you wipe the board and almost guarantee a bigger creature.

If there are 4 players, there will be scenarios where each player just has a couple of big guys rather than a swarm of weenies.

Plus, the token flies, which just automatically makes it different.

I can just imagine the scene where four tiny squirrels get sacrificed in front of the demon's pit, and then this big thing pops out.

Just came back from my first conspiracy draft and I had this; Don't under estimate this card if you are in an almost monoblack deck. What with Tyrant's Choice and other removal happening your opponents will usually not have that many cards on the table. I managed to get my demon out at 15/15 as people were trying for quality not quantity in their creatures and had to sac them as part of the spell.

One thing I didn't notice when drafting was that it ADDs each and every creature's power that is sacrificed, so at worst you are getting a 3/3 flying demon token, but in most cases you are only going to play it when there is little downside to you.

4/5, if it was an instant (which I hope doesn't happen) it'd be a 5/5.

You: Reign of the Pit
Guy 1: Um, I'll sacrifice my pelakka wurm
Guy 2: I'll do my Magus of the Mirror
Guy 3: Hah! A squirrel!
You: Oh yeah, I get 12/12 flier!