Obviously we'd like to see how they turn out in the coming weeks, but initially we're thinking:
1. Too easy to execute
2. Especially in TvT, not a lot of risk to doing them (when you don't lose the Medivac)
3. Might be too early before defenses can be ready
Rather than jumping to conclusions right now, we'll keep a close eye on it and if in fact Hellbat drops do turn out too strong, we'll do something like rolling in some of their damage with the Infernal Pre igniter upgrade.