I remember that fact particularly infuriated a friend of mine, who over the course of vanilla did nothing but PvP, although at the time that meant basically running around Southshore and Tarren Mill. When the honor system was introduced, there was a contest held by Blizzard for those who engaged in PvP, and the top characters on the realm who got the most amount of honorable kills were rewarded with a special tabard. My friend spent weeks in Tarren Mill, happily murdering Alliance until his fingers bled, and he won his tabard handily -- after all, nobody really did as much PvP as he did. Then the Battlegrounds came out.
When he stepped into Battlegrounds, he discovered that despite the fact that he did nothing but PvP, he couldn't hold a candle against those people who engaged in raiding. The gear and weapons that they got from raiding were too powerful. And that's when he threw up his hands, said he didn't want to have to raid to be good at PvP, and promptly stopped playing the game.
The reason I tell this story is because I remember those days, and I remember when there weren't such things as resilience or PvP gear. If you wanted to be good at PvP, you picked up the best PvE gear you could find. The change between now and then is so different that there's no comparing the two. PvPers got their own gear, their own stats, and their own PvP world that they could pretty much live in forever, without having to worry about gear or anything else. My friend would probably be pleased with how much it's changed, though I lost track of him long ago.
Because PvP has its own set of stats, PvP gear isn't exactly the most ideal thing to wear into an instance. Yet for those who PvP all the time nonstop, if they decide they want to see these instances that everyone's been talking about, their PvP gear is their only option. For DPS classes, it's not as much of an issue -- but when you're talking about a tank, heroics are pretty brutal, particularly the latest stretch of heroics. Can it be done? Yes -- but for new healers or healers who aren't decked out in raid gear, it's extremely difficult to do.
So what do we do about this? Should there be an option for a tank set, one that you can purchase with honor points -- one that doesn't have any PvP stats on it but is simply a starter set for those who want to try PvE tanking? Should there be some sort of gear check when you queue as a tank that looks not only at item level but the presence of resilience on gear? Is there a solution, or do healers simply continue to despair when they see a tank in full PvP gear?