Ghostcrawler has wanted to warn us that Armor Penetration is going to undergo some change that will make it "less desirable" for all players since right now there are many players who only choose equipment with Armor Penetration. Although in Cataclysm it will disappear, they do not want to keep it forgotten:
The armor penetration nerf in 3.2.2 is intentional. Compared to the recent upgrade where we increased the Armor Rating value to 125%, this nerf will drop it at 110%. Although we are still evaluating the effects of this change in Patch 3.2.2, we wanted to let you know in case you are considering purchasing a lot of armor penetration gems for your armor.
In fact, this is the point. Many melee players (and Aim Hunters) had started to focus on Armor Penetration at the cost of other stats. Many players were passing the team with no Armor penetration and all gem slots were being tapped for this stat. Although each specialty has more important stats than others, this one seems to be starting to outpace all the others. Players who have accumulated a lot of armor penetration have started doing a lot more damage than we would like.
This change is primarily intended for PvE, although we wouldn't care if melee DPS damage in PvP is reduced as a result of this change.
We wanted to let you know now so you don't feel like an undercover nerf, assuming it hits the servers. While you may not agree or be frustrated by the change (although I suspect many players will not be surprised), we want you to respond appropriately in these forums.
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It's rarely an ideal time to announce a nerf. In the case of, for example, the Nerf to Healing Paladin Protection, we had decided that we were going to fix it and how we were going to do it so we announced it relatively soon. Armor penetration decision has more debate. I'm sorry if the times are too tight for any of you but we can't promise that future nerfs or upgrades will involve changes to the team.
I would not focus much on the problem of always using the same type of gem. There are many situations where the case has been repeated (since it is not an ideal world). The point is, many classes that had been using Agility or Strength or any other attribute, were now switching to Armor Penetration exclusively and were being highly rewarded for it. They forgot about equipment without armor penetration. The talents that benefited from this stat were stacking across all classes. As many players have concluded, it was too good.
That said, we don't think it will become a junk stat if we make this change. If you could take down Plate players in PvP sooner, we don't think this is going to change overnight. We also don't think you need to throw away Armor Penetration gear.
We also think the change is good for both PvE and PvP. My first comment was to try and dissuade players that PvE was going to be nerfed for PvP reasons even though that happens a few times when we can't help it. Some players have complained about the power of melee classes in the Arenas. While this change alone won't convince you, reducing melee DPS damage in PvP is probably not a bad thing.
Yes, the Armor Penetration will go in Cataclysm, at least as an index on the team. Until then we want it to be a good statistic but not one that makes everyone choose it
What do you think? Does it affect you a lot? Did you have all the gear with Armor Penetration gems?