Sadly, however, the motivation to reverse the change did not come via the fact that the nerf was totally class-breaking (stat-wise) and required a complete and utter PvE-revamp. In fact, it wasn't PvE-motivated at all, which is odd because the chief legitimate complaints came from that angle. The change was reversed because of a fluctuation in PvP/Arena demographics, which show Warlocks comprising a lower percentage of high-rated teams than what Blizzard expects them to. As a result, our class's performance in both PvP AND PvE is being left alone... for now.
As you're probably understanding (and probably have understood for a long time now), this change isn't a good thing overall. While this change is great for us Warlocks, it completely emphasizes the fact that Blizzard is 100% arena-oriented. This is an incredibly unfortunate reality for the raiding enthusiast out there, and I'd imagine it's not so hot for PvE devs as well. It means that PvP numbers will change your PvE experience, as Kalgan implied in his comment today:
Locks are doing pretty well overall, but what had us worried was that it appeared to us a month ago or so as though warlocks were on an uptrend. However, the evidence is strong that that trend is reversing, which means significant nerfs aren't really what we want right now (we really don't know where those numbers will settle down).
So, basically, if one class becomes overly represented in the arena, it will get nerfed. When a class is under represented, it will get buffed (as we saw with Druids back in the day). THAT, my friends, is Blizzard's master plan.
Given the outrage of the populace over the PvP/PvE issue, you'd think Blizzard would take note, actually listen to their paying customers, and change their approach to implementing game "balance." Given these recent changes, their motivation, and Kalgan's comments, I guess that's simply not the case.
Maybe hell would have to freeze over again for that to happen.