The Warlocks crying nerf say that it can't possibly be a bug fix because it has been "overlooked" for too long and that it doesn't make sense that the bug only affected the drain spells. Those supporting the change say that healing reducing effects should affect all heals.
Danakha also had a problem with the following change:
Seed of Corruption detonation will now obey line of sight.
But the majority of the forum posters and Eyonix have clarified this as being a definite benefit for everyone. Currently, Seed of Corruption can aggro mobs through walls, wiping raids. Making the detonation obey line of sight should fix the problem.
To me, the real question is: does Blizzard listen to forum complaints and change the game accordingly? Eyonix says no:
We don't make design decisions based upon player complaint. Trust me. You can come up with examples all day long where you believe this is true simply because we happened to make a change that people were complaining about. A change is made after a problem is brought to our attention, we've researched the matter and feel the issue is real.
It's doubtful you'll want to stop and think about the number of things that people have complained about that we never changed, dating back to classic WoW's initial beta -- because it wouldn't support your current perception.
In the past, Blizzard has stated that the perception of Warlocks being OP stems from their ruling the duels. But Blizzard feels that WoW is not a game based on 1v1 prowess and that Warlocks are not over powered when it comes to group PvP and PvE.
So is making Drain and Siphon Life subject to healing and reducing effects a change in policy and a nerf? Or is it a long overlooked bugfix?