Just stepping in for Death Reaper since I helped him design/balance the card in tidbits.
@AngeDeMort:
1. The 'Reap' passive ability removes current active abilities, meaning that growth creatures would lose growth/ablaze, Otyugh would lose Devour, etc.
2. Rage Potion gives +5/6|-5/6 meaning that while it would gain 5/6 attack, it'd lose 10/12 Attack because any damage (Should be health reduction, we agreed on that, but I guess he didn't say that in notes) is inflicted on the attack, and doubled. So it'd be impractical to cast a rage potion on it.
As for killing the creatures once they hit 0|0... I'd have to talk to him about that. The problem I see with that is having 10+ death triggers happen at once when against Mass CC. A RoF would reduce the attack by 6 for each creature, and most death creatures don't have 6+ attack, it'd create a huge chain of death effects at one. However, if it's balanced for that type of scenario to happen, then we may do that.
@AngeDeMort & Anarook: Thanks for the name suggestion to replace undead with. He was actually considering Soulless before you posted it Ange.